My Poor Thumb...

Last night cut my thumb.2 important things I can really do well.The are namely,holding a pen and sms.
When I hold the pen,my thumb will be controlling the movement,but today IT HURTS!
I normally sms with both hands which is already very fast.Today I can only sms with 1 hand and that is the left hand.Quite slow indeed.
Oh my god,why am I so careless?When will it heal?