That's interesting. I see a lot of people shoot HP5+ at 800 and soup it in Rodinal 1+25 and get really great looking prints from it.
Originally Posted by R.Gould
If the OP shot the film at EI 25-50, then all he needs to do is to cut the development time a good bit. By how much is a bit of a guess, because it's about 3-4 stops overexposure compared to box speed. This is why I suggested to shoot one more roll at the same speed and test it first, especially if there are important photos on the other roll. My opinion is that it should be salvageable, and the resulting prints may even be fantastic, but perhaps a little bit lower in contrast than normal.