I learned how to slap..but...

[Lowner]

Ok I Finally learned how to slap and pop But now I have a blister on my right hand index finger that is the size of a pea. Why would that happen?
Maybe it cause I learned from watching Flea slap in his DVD. He really gives the bass a beating and that is what I do to.

[Mr_Dave]

maybe if you've not been working on it long your hand hasn't toughened up in that place yet. perhaps don't practice so long or take more breaks... once your finger has toughened up a bit you should be fine. just like most people get blisters when the first start playing bass fingerstyle...
otherwise try not to slap and pluck too hard. its easy to 'over hit' and pluck the strings and it doesn't always sound so good. just like drums, you can make the skin and stick do the work with rebound, try to apply that to your thumb, finger and strings...

[GSRLessard14]

Your poppin' too hard maybe, or you're just new. Let it heal, then pop away some more.

[Jazz Ad]

Because excessive friction does that to skin.
After a while your skin will grow thicker and it won't happen again.
Never had blisters on fingers when you started playing ?

[PrimusNut]

My fingers are calloused and were before i started playing bass, but i still find that my fret hand fingers get really sore and blistered under the skin. I keep playing, but seeing as yours is pea sized, wait until it gets better. If you would like to still play while its healing i suggest you use a pick.

[Wes]

Mine did that too. Just don't pop for a few days and you'll be fine. They get harder.