I haven't had one myself but my ds has had a heap! One got so big we had to see a specialist who was looking at lancing it if it got any bigger!

Anyway, he said the only real thing you can do is hot water and a flannell. Lots! We do this to ds about 6+ times a day when we see the little red bump starting to hold it back. About 5mins at a time for about 30 blocks. Does that make sense?

HTH