Thank you for your answers. I lowered the temperature and moved the probe on the outside of the container. I took photos of my snake today, and will try to keep handling to a minimum after that.
https://media.discordapp.net/attachm...507&height=675
https://media.discordapp.net/attachm...507&height=675
https://media.discordapp.net/attachm...507&height=675
The first one is the weird scales on her head, the second one is the patch that I noticed after buying him, and the third one is a bit of scales that I noticed just 2 days ago.
My unexperienced diagnosis is that the humidity in the box is too low and his scales are drying. If that's the case, I'll put in a humidity box and spray the substrate once a day with a water mister? sprayer? That.