See, in 'The Beginning', we're shown glimpses of Thomas as a baby and a child, as well as the supervisors reaction to him as a newborn.

As we can see from this picture of Thomas when Luda Mae finds him in the dumpster, most of his 'deformities' are centered around the upper right side of his head, reaching down towards the tops of his eyes.

But in this picture here, we see his 'deformities' have magically moved to the bottom left side of his face, giving him a cleft lip.

And then finally, in these picthres here (which I honestly do not know where they come from, whether they're canon or not, so take it as you will) his 'deformities' have magically disappeared and been replaced by the rare skin condition he began to develop as a young boy.

This change is also reflected on him as an adult, telling me that not only did they not care enough to make his look consistent, but that they just wanted to use it as a scare factor.

Which, as a side note here, I do not condone the act of making slasher's become murderers simply because they are disabled or 'deformed'. I believe this is dehumanizing to real people who have these conditions, BUT I cannot control what I hyperfixate on, nor could I have stopped them from producing this trope, so, it is what it is. I have more of a point of that concerning Thomas anyways, but I'll save that for another post.

Okay! Back to the point. Overall, the people making the movie didn't seem to care about the specifics of Thomas' condition, which, in my mind, leaves it up for grabs.

So! As for my personal headcanon of Thomas, I believe he was never actually born 'deformed'. The supervisor had very obviously never seen a newborn baby before, and if you don't know, most of them come out pretty friggin' ugly. Especially in such a gruesome way.

This is the timeline that I personally follow:

Thomas is born and taken home by Luda Mae.

The Hewitt family isn't particularly popular within town (Luda Mae got pregnant with Hoyt out of wedlock, and was forced to marry his father, who was a drunk), but they weren't hated. They still had (albiet a small) extended family and a few friends about the town.

One of Luda Mae's friends has a son of her own, and when her friends son comes down with the chicken pox, they decide to expose Thomas to it to prevent a worse reaction as an adult.

But Thomas *does* have a bad reaction. A really bad reaction to it. His fever shoots up, running much higher than the other boy, and his body is covered in painful, itchy red bumps that seem more irritated than they should be.

She takes him to the doctor, but there's not much they can do but try to alleviate the symptoms and hope the disease will naturally die down.

And eventually, it does.

Well, kind of.

You see, Thomas had gotten a particularly nasty rash on his face, specifically the lower left half (like the cleft lip picture), and after his fever died down and the rest of the rash faded away or scarred over, that one particular rash just wasn't budging.

And that's because the flare in his immune system caused his dormant skin disease to trigger, and that "rash" was the beginning of it

To clarify; This was always going to happen. Whether they exposed him the chicken pox or not. He always had the disease, it simply lied dormant until a severe immune response triggered it into flaring.

So, his disease progresses, and only grows across the lower half of his face.

Then, when he was about 10 or so, he began self mutilating, and quite literally tried to carve the disease out of his face.

This, of course, didn't work, and it only left the lower half of his face severely deformed, and still diseased ridden.

So, just wanted to clear that up before I dove into this.

As for how Thomas would react to a F!Reader with skin issues, I think it would depend on what time they met.

With childhood friends undertone, I think Tommy was already a very shy child, and considering how awful the other children already were to him, he would be rather closed off and distant, developing anger issues and having outbursts over the years.

This would follow the timeline pretty consistent of:

Toddler - 6: Very shy, scared, and hurt by people's reactions

7-9: He slowly starts becoming very angry and having outbursts, especially as he begins struggling more and more in school

10-12: He begins self mutilating, quietly at first, until he loses control and cuts too deep and has to be taken to the hospital and very likely had to get skin grafts.

At this point it begins to set in that it's truly pointless because he'll never be able to get rid of the disease, and he doesn't necessarily 'mellow' out, but he begins bottling everything up inside, so he's less angry than before, but his outbursts are much more volatile and violent on the rare occasion they do happen.

Meeting someone with skin deformities like himself, I think it's very possible that if he's in a particularly angry part of his life, (think around the time he starts self mutilating), he may see them as an extention of his own insecurities and anger and lash out on them.

If it's before, I think he would be much more inclined to cling to them, trying to self soothe by being kind to someone who's like him.