We all have been in this situation at some time or another, but it sounds like you have gone well beyond the couple of "dents" most of us have experienced.
Unless you are a PWA slalom racer, you will probably never notice the difference in performance, assuming there is some. On the other hand, just knowing that the bottom isn't perfect will probably make you crazy.
I am not an expert on repairs, but you will have to cut out the dents and fill them back in. Is it worth the time and effort?
Formula 160; iSonic 111; HiFly Move 105; Tiga 263; '85 Mistral Superlight.
Maui Sails TR 11.0; 9.2; 8.4; 7.6; 6.6; Maui Sails Switch 6.0; 5.2; Maui Sails Global 4.5; 4.0.