I have a small blister under my foot not sure what it really is. when i put pressure on the area it hurts. it looks like its small round clear thing

Blister: Many things can cause blisters including friction fungus and insect bites. If its painful you should make a small opening at the base of the blister with a sterile instrument. Leave skin in tact , cover with antibiotic cream and band aid. Seek medical help if it fails to resolve or gets worse or appears infected.

With a : Sterile instrument you can gently pierce the roof, allow the fluid to come out, apply an antibiotic and a bandaid. It is possible the pain is from the pressure of the blister.

Possible cyst: This could be a cyst, or a friction blister on the bottom of the foot. Try to sterilize a needle and poke a hole in it. If the fluid that escapes is jelly like, than it is a cyst. If the fluid is clear and thin, than it is just a blister. If it is a cyst, see your podiatrist.