Dr. Terry Dubrow says Jamie Lee Curtis needs to stick to acting and stop bashing plastic surgery ... and he's taking issue with her comparing cosmetic procedures to genocide.

We got the "Botched" star at Mr. Chow in Beverly Hills and our photog asked about Jamie Lee's recent comments on plastic surgery.

ICYMI ... Jamie told the Guardian, "I've been very vocal about the genocide of a generation of women by the cosmeceutical industrial complex, who've disfigured themselves."

Terry says JLC has no clue what she's talking about ... and it's an apples-to-oranges comparison. Plus, he says there's nothing illegal about a little nip-tuck.

The good doc goes even further ... saying Jamie Lee might need some medication for her brain so she doesn't equate genocide with plastic surgery.

We also asked Terry about Brandi Glanville's facial disfiguration saga ... and it sounds like he sees a light at the end of the tunnel for the 'RHOBH' star.