Heat mat burns?

[VantaRay]

Hey guys so I've had a ball python with a heat mat for years without issue, but last weekend I bought my first Milk Snake and I have him on a (tiny 1-5 gal) heat mat in a 20 gal tank. Right under his chin, he's gotten a patch that looks almost transparent on his throat

[ClockwerkBonnet]

A photo will definitely help us figure out what the patch is.

[VantaRay]

It wouldn't allow me to post it right away, but here you go:

https://imgur.com/a/LMknCcR
https://imgur.com/a/LMknCcR