Without knowing for sure, she should start out seeing her regular doctor or she can see her GYN. I would opt more for the GYN. However since it does hurt, this may be the start of a boil. If this is the case, her best bet is to apply a warm compress on the area several times day. This will help draw the pus to open and drain. The warm compress will help with the pain too and taking ibuprofen as well. If the warm compress doesn't help draw it to open, she may need to have them lanced open to drain. But as I stated above, I'm not there to see this, so if you feel this is not the case, then do have her seen by one of the two doctors listed.
Best of luck, Hope this helps, If you need anything else please feel free to ask. If you found this helpful don’t forget to click the *ACCEPT* button and leave *POSITIVE* feedback.