HELP there's a black spot on my hamster's head T^T

[Xennnie]

I don't know when did this, I just cleaned up his cage today and when I bought him outside I thought he just accidentally wet himself again with his sipper water bottle but it wasn't. （ｉДｉ）

Then I noticed this large black spot on his head and he had this small visible cut just beside it, I don't know what it is and I'm worried sick for him and I think he's having a hard time looking around because of it please help I wanna know what to do to help him and I couldn't find the exact words for it in the internet but its not really exactly it (;﹏

[souffle]

You should see a vet and have this checked out. It could be an abscess which has burst and he may need antibiotics and flushed out.
I hope he is checked out soon