It really depends on if the linen pants are new or if they have been worn enough for the crease to get dirty. Flatten the hem edge as much as possible and look to see if there is any discoloration on the hemline. If there is discoloration, I wouldn't bother with them. If all looks good, then take them down and press with a damp facecloth to see if the lines come out. If so, re-hem at the new height. If not, just hem them back to the original line.