I'm writing a character with large, nasty, and veey noticeable burn scars on one part of his face. Any tips on things I should include?
this is what the scars look like
[image description: sketch of a character from the shoulders up with a burn scar on the left side of his face, ear, neck, and shoulder. end image description]
I'm not a burn survivor myself so I'll talk about facial differences in general and link some stuff that might be more specific to your question.
First thing that I noticed about this ask is the wording - calling a facial difference "nasty". Which some people do say about themselves, but I discourage authors who aren't part of the FD community to use that in a neutral setting because it's not a neutral term. Facial differences, including scars, burns, craniofacial conditions, and every other difference aren't ugly, gross, or anything of that sort. Your character does have a large and noticeable burn, true! But he doesn't have anything "nasty" on his face. Neither do real life people with FD who might not want to read about a character looking like them or people from their community being referred to as "nasty" as a state-of-fact neutral descriptor.
To know what to include, you should research the medical side of burns; what kind of burn it is (chemical/thermal/electrical/other? they can cause different symptoms), what exactly is affected and how much (feeling, mobility) and how to care for burns long term (like preventing infections, pain management or physical/occupational therapy). Knowing how burns work outside of being a visual difference will make it more realistic. Researching (referencing) images of actual burn survivors might also be helpful to see how the skin might look like and interact with the rest of the person's face outside just being a different color (compare: a flat port wine stain and a burn scar).
Here is a post about drawing and writing burn survivors specifically. You can also read this post that I made that talks about facial differences in general. It's long but I've heard that it's informative :-) (smiley face)
As always, I heavily encourage anyone making a character with a facial difference to research face equality, as it's vital to making positive representation. I've written more about it in the links above.
I also encourage anyone sending an image to include a description of it so that those of us who use a screenreader can access it as well.