HI Cheryl, I have always found my Peace Lily very thirsty during summer, so I always water them often, then on situations where my peace lily is near death, a careful gently watering really helps them revive again. Twice it has happened to me, one time brought out by mistake so it got too toasty dry and this last August, it got too thirsty indoors while we were away for almost a month. Gently reviving with water, will eventually help it perk up.
It may be acclimating too from the changes you made, so give it time.
My Peace lily looked much worst that that but it came back:
And recently this last August, you can still see the dried out damage on some leaves, but it is now sending me a new leaf:
