black spot on comb

[pertilote]

Pearl, my 3 month old hen, has a black mark/sore on her comb, not sure what it is or what to do about it. No others in coop have same blemish. Advice/suggestions would be wonderful.
Thank you,
Pertilote

 

[Eggcessive]

It is probably a mild case of fowl pox which is transmitted through insect bites, and it should heal in a shot time without treatment. Pecking injuries to the comb can also look like black marks.