The fact that this blister fills with a clear liquid makes me believe that it is only a mucocele. The entire lining of your mouth is covered with small pores that secrete moisture into the mouth. It is possible for one or more of these to become plugged and form a clear blister. This has happened to me many times over the years. When the duct clears, usually when the blister ruptures, it usually goes away

Brian, stage 4 oral cancer survivor. OCF Founder and Director. The first responsibility of a leader is to define reality. The last is to say thank you. In between, the leader is a servant.