My son usually perks up pretty quickly after scopes and is usually starving since he hasn't eaten during the prep. I'd say within an hour he's back to normal and feeling fine - or as fine as he was feeling before the scope. For me personally, it took a good day before I was feeling normal again, so it can vary person to person.
Whether they start meds will depend on the GI and what they see. If IBD is obvious, they may start her on prednisone or EEN like Clash mentioned. Maybe an antibiotic. Once you have confirmation from the biopsies, then the talk will switch to maintenance medications. Read up on these and educate yourself so you can ask questions and understand what her GI suggests.
If you have the time, read through the threads here. There is a lot of good information. Don't hesitate to post questions. Someone here will have an answer or advice.