Red spot on skin

My male cat, two yrs old, has developed a spot that looks somewhat like a scab on the top of his neck. He doesn't meow when it is touched and his behavior hasn't changed at all. I originally noticed it about a week ago, but last night I noticed that it had bled a little. I am thinking it could possibly be a scratch from our other female kitten. Since they were chasing and rolling around before we noticed. They seem to play rough, rolling around jumping on each other. My guess is that it is a result of the playing. Any other suggestions?

I sugest lettinga vet look at it ... may be nothing or could become an abcess or something else