I Feel Saline Implant Valve

From your description it sounds like the implant has flipped back to front, since the valve is a small bump but on the back of the implant there is a patch about the diameter of a quarter with a ridge around the edge. More important is that if you can feel it, your tissue coverage is very thin despite the implant being under the muscle. You may wish to look into the option of  a Strattice graft, which makes a sort of internal bra. This would support repair of the lateral displacement and bottoming out while also adding coverage.

In thin individuals with overfilled saline implants, the valve can sometimes be felt. As for the bottoming out and lateral displacement, it sounds as though your overall tissues are not supporting the implants very well. Consider the use of a dermal matrix (Strattice) to provide an "internal bra" for longer term support. If your muscle has window-shaded and the overlying breast tissue is quite thin, the Strattice can also help camouflage the implant valve. Switching to gel implants will also eliminate the valve issue. Best of luck.