The past tense of give someone a dose of their own medicine is gave someone a dose of their own medicine.
The third-person singular simple present indicative form of give someone a dose of their own medicine is gives someone a dose of their own medicine.
The present participle of give someone a dose of their own medicine is giving someone a dose of their own medicine.
The past participle of give someone a dose of their own medicine is given someone a dose of their own medicine.