Hi, I have multiple small fluid filled sacs/cysts under the skin inside my mouth (not on the skin outside) around my lips, on the sides and under my tongue, painless, I have them for years, years ago one of them used to get bigger so I pierced it with a needle they a are filled with clear yellowish/reddish liquid, When I used to empty it come back the next day and I empty it again (that particular one died no longer gets bigger) I didn't pierce any other one after it.