Do I need an electrician to restore the power to my bedroom on the other side of a wall I drilled into?
It sounds like you drilled into an electrical wire, which will need to be replaced. The amount of difficulty involved in repairing it (and the cost) is mainly going to depend on where the wire is and how easy it is to access.  For example, if it was between two outlets that are accessible from a basement or attic, it should be fairly straight-forward.  If it was a feeder line running through an exterior wall, probably less so.  Fixing it will basically require figuring out what is connected to each end of the wire and running replacement wire.