Back to the OP's question of how to improve the image: The brutal answer is to reshoot it using a more reliable medium. Either with faster film, more light, a better camera or digitally such that the captured image could be verified, and without the intervention of (what appears to be) careless processing. The existing image is, IMO, beyond salvage. There's a vaguely recognisable image of two people standing in front of the camera; too small in the frame, with one in a patterned shirt, but that's about it. Further reconstruction would be more guesswork than factual. I find it quite ironic that the OP insists on shooting film, and yet is looking for a digital means to salvage the mess that film use has left them with.