Roo with Raw Butt, Blackened Comb and Bald Spots Below Comb

[GreenAcresT]

Need some help! I have a 6 mo. lavender orpington roo that has blackened areas on his comb, bald spots on his head below the comb and a really raw butt. I looked at the butt after I noticed his feathers below his tail were all wet. The blackened spots on his comb have been there a while but noticed the bald area last night and then the wet feathers this morning. He's drinking water profusely and looks pretty skinny, but I haven't noticed any diarrhea or bloody poop. I have him isolated now, but don't know what to do next. Appreciate any advice.

 

[Cluky]

does it look something attached him? I guess you need to explain the "raw butt" and comb better

 

[GreenAcresT]

Here's a couple of pictures of the head and the butt. I guess it's possible he got attacked, but it really doesn't look like that (to have happened so suddenly). He's also sneezing and his breathing sounds congested.