Help! Can’t find low back ‘spanx’ pants

[user1486131602]

Help!
My daughter has her prom soon....we have bought a 2nd prom dress today and she needs some help with the tummy area. BUT, she has a backless dress and all shapewear I can find has a high waist at the back!
Has anyone found some with a low back, panties only?? Please?🙏

Would that even be possible? If they're low at the back then they'd be low at the front surely and then wouldn't cover the tummy area.

Sorry if that's not helpful but I don't see how shapewesr for the tummy area would work with a low back but I'm interested if others have some ideas.