I was prescribed amoxicillin and clavulanate for a tooth infection, then switched to clindamycin. i wasn't able to take a bacterial std test before completing the antibiotics. how much would this affect the results and can they be trusted?

Depends on how long you took the antibiotics and the type ov std.

These drugs would have cured most cases of the common bacterial STDs (gonorrhea, chlamydia, syphilis). Finish the treatment as prescribed, then if no symptoms within a week or two, you can be confident you had no STD or were cured. For further reassurance, you could be tested a week or so after your last dose of clindamycin.