Clear bubble on a bug bite? What is it and what should I do?

Nothing. Jerry, insect bites frequently blister. Leave it be, and it will either pop and drain or just get reabsorbed on its own. Hope this helps!
Leave Alone. It is not unusual to get a small "head' or fluid collection at the center of a bug bite. It's best to leave alone, as squeezing it may introduce an infection. Put a little dab of neosporin on it daily. If it is really itchy and bothersome you might try a dose of benadryl (diphenhydramine) by mouth. If it becomes surrounded by a large area of redness or turns black in the middle then you need an exam.