skin condition

Question
  Hello! Well, my boy giunea pig, Glacier, has a skin condition. He is loosing his hair in places like, behind, stomach area, and back. He has had this for a while, but it's getting worse. We think he might have a tumor on his leg, because he keeps biting on his leg. Do you think this would be a good reason to spend money for a vet?

Answer
Hello Lidsey!
Sorry for the wait, I bring good news though if you still want it!
It sound like iether mange mites or lice if there is balding, vet is required for this. The vet will give you either a eye dropper with a clear liquid that you just put behind there neck or an oral medication. Perhaps a shot as well, this is usually optional.
It could also just be him scratching. I do not suspect any tumors, they would have much different signs. My own girls have a genetic dry skin problam, so they got it from there mom and gave it to there own three sons and four daughters. This is no worry and not a serious thing. The vet will presribe extra hiar brushing time!
I suggest taking them to the vet though ASAP.