I hurt (strained) both thumbs over several months lifting (bench pressing mostly) several years ago. I think what happened is that I got stronger so quickly (not though AAS) that my tendons and/or ligaments couldn't keep up. I though WTF, no-one gets thumb injuries from lifting, so I continuted, assuming it was just a passing 'thing' and would get better.
It got bad very quickly, coupled with being used al the time in daily activities that, I had to take 18 months off, and still have issues benching now, 2 years later.
Not sure what to take from this (probably not the same thing), except perhaps to take the injury as seriously as something like a shoulder and make sure it is getting better and not worse if you continue lifting through it.