I have a suggestion for you: Get a second opinion (and perhaps a third) opinion from other retinal specialists. Unless you have a macular hole or a retinal detachment, there is no reason for face down posturing after a vitrectomy to peel an ERM.
The retina is nerve tissue and heals slowly. Full visual recovery takes 3-6 months or longer. Your chances for a good outcome (in terms of improved acuity and reduced distortion) are best if surgery is done within 10 months of the development of the ERM. Of course, your choice of surgeon is extremely important. You want a doctor who is very experienced with this procedure.
Use the search feature and archives to read the extended discussions about epiretinal mem brane peels, comments by patients having the surgery. All agree that it is big time surgery and cannot always restore the eye to "perfect" but can often improve or at least keep from getting worse.
JCHMD