The talent reads, "When making a medicine check to help a character heal wounds, the target heals one additional wound per rank of surgeon."

Technically, it doesn't say you have to succeed on the roll. The player didn't succeed, and I let it heal one wound anyways.. thoughts?

Interesting, I have always allowed it, but it could go either way. I have considered that their training effectively means they will make some form of improvement to the condition of the Character even if its not much.

Any skill check always requires you to be successful. This was asked and answered. If you don't succeed you can't help someone heal wounds better if you failed.