What Causes Recurring Blisters On My Penis?

I have a reoccuring issue in that I find what looks like an inflamation or white-ish, in color, lumps or 'bubbles' if you will just inside the tip of my penis. I have only noticed it twice, the first about 2 maybe 3 weeks ago, the second time was earlier today.



If the lumps burst or pop they bleed out continuously for a duration of roughly 10-20 minutes which I spend in the shower rinsing.



I'm very concerned as to what the cause of this is and just what exactly this would be called.