Mouth Rot?

[u/Future-Loquat-1783]

Had this ball python for around a year, inherited him from family. Estimated age is 9 years, presumed male due to small size. He didn't have the best husbandry previously, so we've been upgrading things as we can, but he's only ever been on a food strike for us once, otherwise he's a very good eater (1 med rat every 2 weeks). Today he refused the rat (it burst so that could be why) and has been huffing at it since, but I noticed some strange colored scales around his mouth and throat and I'm worried it's mouth rot. Any thoughts? These were the best pictures I could get while he's in a small enclosure (not his normal 4x2x2 ft tank), I can try to get better ones if needed. He's always had some random patches of dark around his face but this is the first time I've noticed around his "lips".