Dear friend, welcome and thanks for entrusting your query here at Healthcaremagic!
I am Dr. Prasad Akole (Critical Care Expert- http://bit.ly/Dr-Prasad-Akole) and am glad to address to your query here.
Take simple pain killers like OTC paracetamol
upto 1 gram 4 times a day.
Watch if there is any swelling, tightening within the plaster, discoloration of the thumb, loss of sensation at the tip.
If any of these is there, please see your ortho doctor immediately. Sometimes swelling inside the plaster can cause these and pain.
I hope to have answered your query satisfactorily. I would be glad to answer any further queries. Take care and please keep me informed of your progress at http://bit.ly/Dr-Prasad-Akole