Sounds like you had a Paronychia or Felon. My wife had one after reaching into a Coke box and sticking a corner flap under her fingernail. A week later, it was quite inflamed and painful. The Dr. nearly sent her to a hand specialist after his initial treatment of draining and inserting a wick didn't work. He prescriped a strong antibiotic and hot water & Epsom soaks several times daily, which did the trick. If the pus pocket is is not relieved, it can infect the bone and that would really ruin a vacation.

Kodet and Angier's "Being Your Own Wilderness Doctor" recommends a 11 Bard-Parker scaplel and a "fish mouth" type incision into the pus pocket to relieve the pus. "This is not a pleasent procedure to undergo, but neglect will cause even more unpleasentness".

I found a copy of the book for 50¢ at Goodwill and scanned it into PDF. Makes a good addition to the FAK, even though it's 1968 vintage.