I have been using revitalash for 5 months and the lashes are only growing on one eye. Has revitalash caused this?

there is only 1 product which is FDA approved for treatment of eyelashes.  There is no scientific information available about Revitalash.  If you are interested in using a product to stimulate eyelash growth, I would strongly recommend switching to Latisse.

There are no FDA studies or reports for Revitalash like there are for Latisse. If using Revitalash is the only thing you have changed in your regimen, then it is most likely causing this. But there's really no way to know for sure because Revitalash doesn't have studies or safety reports. "This
answer has been solicited without seeing this patient and cannot be
held as true medical advice, but only opinion. Seek in-person treatment
with a trained medical professional for appropriate care."