Hi Karen,
Yes, Uhthoff’s phenomenon is temporary (<24 hours) and is not indicative of a relapse or exacerbation. Interestingly, Uhthoff's phenomenon was once used as in the diagnosis of MS ("hot bath test") before MRI and CSF analysis were as advanced as they are now.
I don't recommend spending time memorizing the names and administration routes and timelines for the medications. I think understanding that different medications are used for managing relapses versus disease-modifying pharmacologic therapies and that various routes of administration are used is sufficient. There's a chance something super specific could sneak onto the test, but this is unlikely and your time is likely better spent on bigger topics.