For 8 months now: Persistant tiny clear blisters (with red dot in center) on hard palate. Appeared suddenly. Now thickened skin where blisters have coalesced. Skin under/around blisters is sore (hurts like a scrape or burn wound). No pathogen found in tests. Picture: https://postimg.cc/LnkfN95s. What can this be? Multiple superficial mucoceles... or something else? Any ideas? And how do I get rid of this? Please help!