Is vaping okay after gastric bypass?

I would strongly recommend that you quit the habit before and after your surgery. we don't know for sure what ingredients are used in these vaping liquids. Smoking in any form (whether cigarettes or e-cigarettes, or vapers) has been linked to an awkward and infectious post-surgical recovery.

in addition to the health risks you expose yourself to while smoking.

Gastric bypass was part of a move on your part to change your life and get healthy.  There's nothing healthy about inhaling vaporized nicotine.  Can you do it in moderation?  Sure.  You can also occasionally shoot up heroin, snort cocaine, smoke weed, and drink alcohol.  Why not give it up and get some healthy habits?