A tumble through the dryer can shrink your pants, making them too short. Pants that are too short can look silly, but you can save them with a little sewing skill. Undo the hem and make a new one a bit lower to restore the cool look to your jeans or pants.
With a seam ripper, remove the original hems in the pants.
Iron the pants legs flat.
Cut away fringe, if necessary.
Create a new, smaller hem on each leg by folding the raw edge up to the old fold in the fabric. Pin the new hem in place.
Sew the new hem on each leg.