Currently, you can't. Salesman Rick's does not sell a revive item until after you battle Rick Prime in the Citadel of Ricks, and you can't get back to the Citadel to the healing center unless all of your Mortys become dazed.
After you battle Rick Prime (the first Rick you battle in the Citadel), Salesman Rick's sells Halzingers for 650 Schmeckles, which restore a dazed Morty to 50% HP. You can also craft Halzingers as well.
Alternatively, you can always just have your Mortys become dazed. There is no penalty for letting your Mortys die. Birdperson will take you back to the healing center for free. This is also useful if your Mortys are out of AP.