S.D.
I see that your son was in an accident and from there started to use the potty maybe at that time he felt if I pottied on the floor i'll get into trouble so he did it.Now after a few months he is regressing because maybe his body wasn't actually ready to be potty trained.I have asked this with my second child she is interested in the potty but she is only 19 months old and don't want to force her I feel as if my son we were a lil harder on him because he absolutley refused to poop he'd wait till a week later and then go into the potty.Needless to say I had to take him into see the pediatrician I thought something was seriously wrong with him when he calasped in pain and tears at the store.If you are sure you want to continue to potty train your son then do it and be consistant I had to with mine,he was under 3 and then fully potty trained at 3 now going on 5 yrs old only had an accident or 2 in the past 2 yrs.Reward system is nice it shows them gratitude and acheievment at a young age.If he poops I gave my son a sucker to say JOB WELL DONE it won't last long I thought it would be never ending a sucker after ever poop but after a good month or 2 he was fine.Good Luck and if he slacks off now than later it'll be fine.Just a lil encouragement from his mama.It is frustrating.