If I pop a boil, will anything bad occur?

Best to see a doc. It's better to get pus out than to leave it in. However, the disadvantage of doing it yourself is that you can't be sure you're completely emptying the abscess. In addition, unless a deep abscess is packed with sterile dressing, it may close from the outside first, allowing reaccumulation of the pus inside. We prefer that it heal from the inside out.