What is this?

I noticed this today. As soon as I seen it, I brushed my sons teeth, then looked and it was still there, so I brushed in that area again, looked as is still there then I noticed that it’s blood? (It was like this BEFORE I brushed his teeth today)

He’s 1 years old. Breast fed. He does not have any kind of junk food, doesn’t drink juice at all and the only milk he drinks is breast milk. He loves his fruits & cheese !

I’m going to make an appointment tomorrow. It’s 9pm here.

But just seeing if anyone possibly knows what this is? This is the best picture I could get.. my son absolutely haaaaates getting his teeth brushed, he always has. I do brush his teeth everyday!