Could hair grow back that was lost from stress?

Yes it could but you will need to treat or diffuse the cause of the stress.

Quite often it does.: Ways to address stress. Talk about feelings ; address problems. Don't avoid them. Aim for 7.5 - 8 hours of sleep/ night. Daily physical activity is optimal in a green space. Eat healthfully. Cut out junk carbs, caffeine ; alcohol (or moderate). Try qi gong, tai chi, acupuncture, acupressure, homeopathy, meditation, yoga, exercise program, deep breathing exercises or progressive muscle relaxation.