My husband had left inguinal hernia surgery 10 days ago. Left testicle swollen, hard and is up very high near groin. Is this normal? When will it drop

Most likely. Your husband's testis is hopefully just inflamed from the mesh used. However to be safe you should have him see his doctor. .
Post Op Complication. Please have your husband contact the surgeon. He would have been given specific post operative instructions to take home. These instructions will describe what is normal and not normal and how to contact the surgeon should a post op complication arise.