one time when it was raining , i called my first saint (smore) into a camper i had. the electical cord to thew camper got wet. when she stepped onto the metal step she got zapped! she was my best ever behaved dog who did EVERYTHING i asked, well she turned tail and ran 3 blocks away without ever looking back no matter how much i called.
the reason i tell this story is she became extremly afraid of that camper and would go nowhere near it. after a few months i started to try to get her back into the camper. with alot of work she would jump right in (never again did she step on the step though)
all i am saying is give your dog some time to get over the trauma of the accident. if it just happened this weekend and at first he/ she didn't react it could have been the meds had her/him doped just enough to forget, but once she/he remembered he/she freaked. give some time, maybe after the staples come out but don't baby or act too different or change your routine b/c sooner or later your dog will want to go back to the fun life you used to enjoy