I would see a dermatologist, it is best to get something like this taken care of before it gets worse.
Hi,
I think that you see a doctor just to be safe and ensure that you are taking good care of yourself. Is it linked to your menstrual cycle ? Does the abscess ever break ?
Really, so visit your doctor and put your mind at east and prevent this from developing into something worse. It may be cured by something as simple as an antibiotic and then you are free !! Hope this helps you.
If it's an abscess, you should see a doctor. By any chance did a cat scratch you? Could be cat scratch fever, which requires antibiotics and often having the abscess drained.
If it's partly draining and refilling, yes, it would seem to come and go.