Can Steroid Injection For Bronchitis Cause Caving-in On Injection Site?

My active 79 year old mother-in-law received a shot in the hip for acute bronchitis. She was told that the injection was a steroid. Since that time, the area of the injection has caved in with a pea sized bump at the center of the site of the injection. The area is two inches in diameter and about a half inch deep. There was no pain associated with the aftermath. She is about 5 -2 , 100 pounds soaking wet and a history of osteoporosis, nonsmoker, no alcohol, no diabetes. Do you know what would cause such a reaction and what can be done to restore the tissue. It does bother her when she see s herself in the mirror. Any ideas on cause and remedies? Mike, Roseville, MN