You need to see a doctor. Leaving in a tampon for too long can cause toxic shock syndrome (TSS). If you got a fever, you need to get checked out. I know the fever is down right now, but since you're in pain, you need urgent care or the ER. Keep up with tylenol, aspirin, or ibuprofen to keep the fever in check.
CALL 911 AND GO TO ER RIGHT NOW!!! YOU HAVE TOXIC SHOCK SYNDROME AND IT CAN BE FATAL IF UNTREATED!!! - Blu
Oh, we don't know if you have toxic shock syndrome as we can't diagnose anyone on a pubilc forum.
I do recommend that you call your doctor right away and be seen though. good luck