I bought these Nike shorts and it’s a little too big, it’s 100% polyester if that helps….
If you shrink it in the dryer, the fabric can sink and look old.
I don’t think there is any other way than to flip it over and get a smaller size.
If they’re cotton, maybe. Wash in very hot water and place in a very hot dryer longer than needed to dry. If they are made of synthetic material, your option is to gain weight.
wash with fabric softener and dry for about 20 minutes
you can take it to the tailor to get it repaired