Turtle was lost in backyrd winter 2020-21. Tho relatively mild, there were 5-6(?) freezing nites. He didn't bury deep enuf & top half of keratin froze off, leaving him mostly "bald". 5 mos after he was found "black stuff" started growing UNDER shell at seams of scutes. Is the black replacement keratin? or? He acts ok. (the single herp-vet in Eugene,Ore. is NO help at all.) Tried attaching pic w/o luck.