If the whole screw loosened and fell out, went down the drain, yes, it's a matter of finding a screw that will work. Take it all to a hardware, plumbing supply or box store and match it up.
If the screw broke off in the stem, you will need a back out to remove it before a new screw can thread on.
If the screw broke off in the stem, you will need a back out to remove it before a new screw can thread on.
