The purple colouring is the remains of the 'anti-halation' dye, originally put there to reduce the effect of light reflecting off the back of the film.(posted 8720 days ago)
It won't affect the permanence of the silver image, but what I've found from experience is that any remaining dye isn't stable. It fades on exposure to air and light, and eventually you'll have an uneven magenta stain overlaying the silver image. This still isn't a disaster, unless you want to print the film on VC paper.