Feeling dull ache in my outer hand on the metacarpal of the index finger it came on dying bicep curls. i rested it for a couple months, but still the?

Hand surgeon: I am concerned that avoiding stress on that joint hasn't resulted in resolution of discomfort after 2 months. To avoid permanent damage to the joint, I recommend a consultation with a hand surgeon for diagnosis and treatment before you resume exercising again.

Hard to say: There are multiple possibilities. You could have ruptured an extensor to the index finger, as that finger has two extensor tendons and so you would still have extension of the finger if you ruptured one, it could be a variant of carpal tunnel syndrome in that the median nerve does supply the index finger. A hand specialist would likely be able to tell you, don't hesitate to be seen.