Huge soft lump after fat transfer to under eyes. 3-weeks post op no improvement plus eye bag. Can revision fix this? (Photo)

im not a fat of fat grafting to tha area much anymore fillers are more elegant. however, now that you are In this situation Injections and.or RF microneedling can help.  I would suggest LED right light and eye rolling at home now (see link to emeragecosmetics.com) then coming to see me asap.  
There is no permanent reversal to fat grafting unless its surgically or liposuction removal.  You can try steroids + 5FU + hyaliuronidase with or without RF treatments like venus legacy and exilis ultra to get improvement. I suggest you see an expert for an evaluation.  Best, Dr. Emer. 

Yes treatment can be done. Need personal evaluation to determine what and when it should be done. See an expert.

I appreciate your concern and frustration, however sometimes problems such as yours does occur from fat grafting to the face, especially the lower eyelids.The skin is very thin in this region and if the fat migrates even a little bit after placement in the deepest portion, issues like yours can occur. However the good news is that it can readily be fixed, but I would wait one more month to allow all swelling to resolve and be certain it does not improve with daily massage. If needed, placement of a minuscule incision and teasing the displaced fat out of the area  will correct the issue. If your doctor was not a board-certified plastic surgeon, get a second opinion, Or discuss my recommendation with your surgeon. Good luck.

this is grafted fat and in my 35 year experience with injected fat  it is not always easy to remove.  if the fat was  placed on the bone or in a circumscribed area it is easier.....on the other hand if the fat is in all layers of the eyelid it can be quite challenging. You need to see someone who has done this quite a bit. 
by the look of this it looks as if it might be amenable to removal