I had quite a lot of these while breastfeeding. What worked for me was a sterile needle...I remember one time sitting up at 3am blurry eyed and trying to poke out the blister with a needle It is very scary at first and must be done very carefully since this blisters can be so tiny!!
If you dont't want to use a needle you can place a warm face washer over the nipple and when it is softened try and scrape it gently with fingernail or a face washer. Or you could also soak your nipple in some warm water or under the shower and do the same.
Keep feeding your baby as much as possible from the affected side, as excruciatingly painful as it can be... but I have heard that some babies are able to suck the blister out and the milk is released. If baby can do this you might find a sudden gush of backed up milk and a huge relief!!
There's more info here: https://www.breastfeeding.asn.au/bfi...te-spot-nipple
I really hope it resolves for you! It's no fun having them at all!