I don't know that much about macro parasites but it sounds more likely that they are related to a bacterial infection. If they are filled with puss, then they certainly are. If that is the case, you may have a underpowered immune system. The most effective(and fastest) way to activate your immune system is starting an exercise program.
If they should turn up to be actually parasite related, then you need immidiate treatment with an Antibiotic that will kill cysts, maybe for many months.Though it's more likely to be a bacteria such as staph. Try if you can crack one open and see what it smells like.