Hello, i think i have a ringworm at the back of my knee, it's a red circle but normal skin inside, it's not itchy or painful, i have put germaline on?

See a dermatologist: If this does not promptly clear up with the treatment you are using you should let a doctor see this and treat it appropriately. Good luck.

Psoriasis: I think this could be a ring worm but it is just as likely to be the common skin condition known as psoriasis. Your family physician should be able to easily distinguish this for you and recommend appropriate treatment.