Recruiting Gypsy maybe a good idea but, have you forgot how freaking stubborn and reluctant she is?
I think Wally healed faster then expected and was able to get Iris out of there and switch her with HR who used his thingy to replace her.
They used it this episode to show us it could do a whole body and not just the face, plus the fact that HR was incredibly guilty about blabbing and he was just grumbling how he feels he really doesn't contribute anything.
In fact I am 99% certain this is what has happened. Of course the problem with that is if later it turns out she is alive - Savitar would know this because once Barry found out he would know.
But they also showed that Savitar's memories of the past change as Barry messes with the timeline. He did not remember Snart got recruited until it actually happened 'now'.
What would be cool is if we get another Wells to replace him. Either the E2 one moves back or they recruit another.