if you have a leek in a line you really need to replace that section of line if its at a fitting you can usually take it off and put Teflon tape or plumbers putty on the threads and re install and tighten it to stop the leak. also there should be at the least a bead of caulk around the frame of the shower door/walls if that's the area you are referring to. If you still have a leak at the fittings it will come back to haunt you in the future if you don't completely fix it now. experience is sometimes a costly teacher.