How do you fix a broken thumb?

Go to the doctor and get an x ray to clarify you will generally get a cast for abOut a month,if you don't want to go to the doctor then. The symPtoms for a broken thumb are

Swelling

Pain

Discoloration

Mobility(sometimes you can still move thumb)

If you have 2or3 of these you can get a real cheep splint at a local pharmacy.