Severn joined the Iron this summer as back-up to No.1 Sam Slocombe, but with Steve Mildenhall on loan has found himself out of the matchday squad altogether.
He made three appearances for Tamorth in October in a loan spell from his previous club Derby County, and will spend the next month at the Lambs.
His move is clearly designed to free up space for Brian Laws, the Iron manager, to add to his squad before Thursday's loan deadline.