There is a lot more in the venom than just formic acid. It is not the acidity of the venom that causes the pain. Even if it was then adding chlorine bleach which is an acid should make it worse.

Household bleach and ammonia are both pretty harsh chemicals. Be sure to dilute them and remember to never mix the two.
Household bleach is strong enough to burn human skin. Don't put it on stings

Ammonia seems to be more effective than bleach and is the base for a lot of sting lotions.
The classic would be the "After Bite" dauber.
I am not sure but I think they use a solution of about 3% ammonia.

I will repeat this statement, Chlorine bleach will burn your skin if you are not careful to dilute it a lot. It is dangerous material.