Hi I am glad your son is alright......
As far as if the ER doctor will get involved well I believe anything like this or cut and bruised up kids (regardless of how it happened) they have to make note of it.I can't say weather a social worker will be at your door or not but probably a possibility.Try not to beat yourself up too much it was an accident of course you did'nt think your son would get a hold of your pills.I would sugesst putting your pills higher up though.I put all over the counter pain pills,medications in a basket on top of my refridgerator and hey for some kids thats still not high enough some can climb like mountain climbers

.You may even want to get you a small lock box and lock your medication up in that and put it up high on a shelf or something.I would do this asap for the saftey of the child of course and since you may be getting a visit.Also I would talk to the child about how important it is to never ever touch pills or pill bottles.