Waterproof blue lip stain?

Sephora Collection matte cream lip stain liquid lipstick in shade sea mist ($14)

Yes. Ofra Beauty Supply (google them) through Ulta Cosmetics. They carry Blue Lip Stains. They will stay on for a long time. Even though eating/drinking/ swimming. I have Blackberry and Turquoise. You can only get them online. They are $17.00.

You won't find one. Lip stains work because they contain specific acids that change color when they react with your skin, that's why many lip stains start out one color and move toward a brighter, pinker or orange tone as they wear off, the pigment in the product wears off and reveals the vibrant stain that's left behind. If you've bought "mood" lipstick, you know what I mean, those are the same acids and tend to turn bright pink or orange.

There's no chemical that can stain your skin blue and is also safe for licking, at least not so far, trust me I'd buy that product if it existed. So while you can get lots of transfer resistant blue lip products, you won't find a true blue lip stain.

No guarantee, but you can get this at Target:

https://www.target.com/p/nyx-professional-174-make...