Without knowing anything about your case, the only thing I can suggest that might work is Arnica (try a 30 first, then if it's not enough, try a 200) to palliate the shock of the flashbacks (not to be used long-term), although thorough homoeopathic treatment over a period of time is adviseable.

Good luck.

I would advise homoeopathy with a good homoeopath instead of drugs, since drugs won't cure, and homoeopathic remedies, well-prescribed can do in a few weeks what therapy can take years to achieve.