He's a year old, I noticed it a few days ago. He's been a little more docile lately but I think that's because he was shedding, he's done shedding now but the plaque is still there. He is not dehydrated, lethargic, or sick in any way. They look slightly painful when I touch it. I thought it was a burn at first so I switched his heat bulb to a 75 watt in a 50 gallon tank. The distance between the basking spot and the lamp is 7 inches.