If its damage to the surface of the groove then i am afraid the hiss might not go away. This could be caused by excessive wear and use of the record (though I have heard recently that if used with a correctly set up system, records shouldnt wear out at all even after repeated usage) or incorrectly set up TT/Cartridge (this one is a common offender). If spending a substantial amount on a pre owned LP, it might be a good idea to see what cartridge and equipment the previous owner used or the general condition of his records to get a slight idea.
Hiss caused by embedded dirt in the grooves of the record will go away after a thorough clean.