Unlikely to be broken, generally you'd know you broke something immediately it happens. Not something you're likely to forget.
Most likely it is garden variety osteoarthritis.
Rheumatoid and gout would be the next most likely. Rheumatoid doesn't affect the end knuckle of fingers for some reason.
Least likely would be an infection in the joint. This would be exquisitely painful to the point you would not be able to move it hardly at all due to pain.
Safest drug treatment would be paracetamol as per instructions on the box, generally 8 - 10 a day. Other drugs like ibuprofen are effective, but may have serious side effects like stomach ulcers.
I'm not talking about correction of serious deformities like cleft palates. I am referring to people that have some delusional belief that making their lips plumper will make their dysfunctional relationship into some perfect romance.
RE: I asked a man
Quorum. Aramis is a good alternative.