No. A penile implant is not a prosthesis in the conventional sense. It does not replace the penis itself, but only substitutes the erectile tissue. The implant is inserted into the corpora cavernosa so the entire system is hidden inside the body. With no visible scar remaining either, other people will not be able to tell that you have an implant. In the shower at the gym or in a sauna, no one will suspect anything.
Even sexual partners will usually not notice any difference from a normal erect member.