Can I use weights to build up some muscle?

Weight Training. If you have any medical concerns as to why you could not begin weight training consult with your doctor. Otherwise, if you are medically cleared, there should be no reason why you couldn't begin a weight training program. Start slowly and if you unfamiliar with weight resistance routines consult with an exercise physiologist. My best.
Yes. As long as you don't have any health issues holding you back from lifting weights, this can be a great way to increase your muscle mass. Make sure you are being smart and safe. Consult a trained specialist at your gym to help you get started if you need to. If you have any pre-existing health problems that you think may be an issue, consult your physician.