Let him go

Rex crawls off, nursing his injured dick. You, worried of what might happen when he gets back, decide it in your best interests to leave, chastity in place.

Rex’s dick was as good as gone, he saved himself a single inch of penis. Unable to obtain an erection, his nub was as worthless as yours. You did end up getting the key to your chastity a month later, and you were free to live with an erection never in excess of three inches. Rex was right about that much, you never grew into anything, but what could you have used it for anyway?