"Don't heat them you will get a bigger bubble...". I do agree with Lee that heating may get you bigger bubbles. I must add that in the case of uncured foam, it's like having little time bombs that will eventually all cure when exposed to enough heat or sunlight. The problem is that they will not cure at the same time. Each time a spot gets hot enough another bubble will appear. To make sure that you only have to do the repairs once, applying heat will cause the remainder of any foam to cure and then you can fix them all at once. Mark this is a just in case recommendation. You never said what you think was the cause of the bubbles in the first place. This problem with using spray foam has been documented before and a lot of builders avoid it's use for this reason.
Orma Southfield, MI KR-2 N110LR 1984 See Tweety at http://www.kr-2.aviation-mechanics.com See other KR spces at www.kr-2.aviation-mechanics.com/krinfo.htm