Wilmer Valderrama & Minka Kelly ¡Ay, Dios Mio ... Vacay Wore Us OUT!

9/6/2016 12:57 PM PDT

Wilmer Valderrama and Minka Kelly need a vacay from their vacay, 'cause nothing about their faces says rested after a weekend trip to Mexico. 

The one-time exes looked pretty officially back together as they boarded a plane Monday in Cabo San Lucas. We're guessing the getaway included some relaxation -- we saw 'em lounging by the pool -- but sleep appears to be a whole other story.

Catching ZZZs is overrated ... when you've got a hot piece.