Part of my foreskin has swollen into a bubble after masturbating with lube. it isnt painful, but is freaking me out still. it is the same color as my non-swollen parts of foreskin, and it is not irritated or itchy at all. what should i do about it?

It is not feasible to provide a meaningful opinion without additional history, and physical examination. What you described could be due to rupture a small blood vessel and formation a hematoma. You may watch and wait. If lesion becomes painful, ulcerates, you get fever, or the lesion spreads, see a doctor. You may use warm fomentation to facilitate the resolution. Color changes are not a concern.

Give your penis a rest and use warm soaks several times a day for a few days. If not better in a few days. you will have to be examined by a Urologist for cause. Do not use that lube again.