Hi Chris, and welcome to APUG,

Your problem looks to me like an in-camera light leak. Does this happen on every film? Light leaks can be very elusive, and may only cause a problem if (say) bright sunshine hits the camera at a certain angle.

What camera are you using? It might be useful info because others may have had similar problems with that model or make, and light seals do vary in quality and deteriorate with age and general wear.

If this only appears on the final few frames, check the camera's light seals around the areas where the spools are seated; but check them all anyway! I had a similar problem with my Yashica TLR, which only occurred on the first four frames of a film. As the width of the feed spool decreased, the film was moving away from the light leak. I replaced the seal around the door and it was gone.

You might run another roll through the camera and see if you can replicate the problem if you haven't already done so.

Cheers,
kevs