Really cramped hand from bass guitar! Help!?!

Really cramped hand from bass guitar! Help!?

Since it's my holidays I've had alot more time to practice bass, and all up I've done about 5 hours of playing today and have been doing that for the past 3 days and just tonight my hand started cramping up really badly, now it's very stiff and sore.

I know it's a matter of perseverance and it will get stronger, but is there anything I can do to relieve the pain just for a short while?

Thanks!

3 weeks ago
(And please don't answer: stop playing bass. I just need a way to soothe the muscles a bit so it's ok for tommorow!)

RICE - Rest, Ice, Compress, Elevate... for the first 24 hours, then apply heat.

Get a racketball ball or an old tennis ball and start squeezing it to strengthen your grip. You might use two ballas to keep both hands equal.

You can go to the local gym and tell them you want exercises to strengthen your hands... Things like crumbling paper with one hand, and rolling a broomhandle with a string and lite weight on it...