I agree to see a doctor. Most definitely. I don't know if this is something like what you are talking about: https://www.mayoclinic.org/diseases-conditions/molluscum-contagiosum/symptoms-causes/syc-20375226 They don't really become fluid filled though and I'm not sure if you are saying that is what is happening. It could have been initially allergic reaction to the lube you used but it's lingering and comes back? Do you still use that lube? But really, hard to decipher what is happening and I'd go see a doctor as oculus12 suggests.
Hi! If it still occurs, you should visit an urologist. From the description alone it is impossible to say what it is. It could be a sexually transmitted disease or something as harmless as contact dermatitis because of a lubricant or tissues... Stay safe.