I assume you are referring to a roll of 120 or 220 film, or something of the like. Most likely your shots are not totally "ruined" but may have some light leaks on the edges, probably for 1/2 or 3/4 of the roll depending on the severity of its unwinding. Process it as normal and save what you can, you may need intensive cropping but most should be able to be salvaged, expect about 1 or 2 ruined frames at minimum so you don't have a huge shock when opening the dev tank, again i dont know how much it unravelled but its probably only as much as normally do for mine when not tightly packed. If the roll is ruined after processing, use the remaining effective densities for tests and comparisons.