Dd had a concussion 3 years ago. The best thing I can say is its best to be overly-cautious and restrict activities at the beginning, then start reintroducing in amounts they can tolerate but stop when they cannot..and know it may take time.
Hard to remember all the details, but the concussion was originally missed for dd who got the concussion because she had a seizure/syncope and fell--so the attention was on the figuring out the seizure/syncope part. She could not be in large crowds, deal with loud noises, deal with crowds, got a lot of head aches, attention span was awful and some other things I cannot remember. It was so frustrating for her, as it was the end of the school year, she is a major band person, and she had to miss some awesome end of the year band activities.
Its hard to remember how long it took to recover. I feel like there probably were small changes at 1 month and then bigger at 3 months and 6 monts. Sorry if I am scaring you;hopefully it will be quicker, for your ds but that is how long it took for dd..I feel like attention span and headaches were the longest-staying...and I will say she has made a full recovery. She gets headaches, but since she has a long period of time without them, I really dont think they are from the concussion
She was not put on any medication other than something called Migrelief, which helped a lot with headaches. Its OTC and I think has b vitamins and magnesium.
Best of luck to your ds. Getting into a specialist early is very positive as it is important to make accommodations/changes sooner if necessary and this helps healing.
lucky single mom to 20 yr old dd and 17 yr old ds through 2 very different adoption routes