Indoor cat with facial bleeding

Question
Our cat started to bleed out of a sore on his chin just under his lip. It was not bleeding profusely, but it wouldn't stop bleeding for almost an hour. He is an indoor cat and has gotten outside, but has never encountered another cat outdoors. The last time he got out was a few days ago, and all he did was roll in some dirt. What could cause his facial bleeding?

Answer
Well of course without being able to see the cat there is no way for me to know why his chin is bleeding. Most common causes are:

Cat fights, bites, scratches.
Feline acne-which is just what it says. They get blackheads and pus filled pimples under their chin that can bleed at the slightest touch.
Cuts from wires, wood, nails etc.
Even bug bites can bleed.

Your best bet would be to take him in to the vets and have his chin looked at. He may need some antibiotics as well.

If he has feline acne, the vet will treat it then show you how to clean it at home. It needs to be scrubbed twice daily with a special solution the vet will give you. Some vets use a cream after scrubbing, some do not.

In any case, the vet really needs to see this cat's chin before it gets really infected.