I have braces and my teeth are ok, and I have really swollen gums how can I unswell my gums?

Oral hygiene. Try to brush and floss at least twice a day and be very meticulous. If it doesn't resolve, you may need to see your dentist to get treated.
Improve your hygiene. Typically swollen tissues during braces is due to plaque/bacteria. Try using an interproximal brush to clean around and under brackets and wires before brushing.
Hygiene issue. Rarely this is due to allergy to the nickel in the stainless steel. Usually swelling caused by allowing bacteria to collect next to hour gums. You probably need to achieve a higher level of personal oral hygiene. Brush 2 min by the clock 2x/day. Clean between teeth w floss and/or proxibrush and water pik. If swelling doesn't resolve, think about consult w periodontist.
Brushing, cleaning. Gingivitis or swollen gum tissue is most often caused by inadequate oral hygiene during braces. Angling your tooth brush bristles into the tooth and gum tissue union and gently massaging while watching tv or using computer is suggested. Healthy tissue will typically not bleed. Ask your orthodontic specialist if a prescription rinse might be helpful in your situation.