It sounds to me that your husband's ear drum is damaged. Hopefully, the spark did not damage his middle ear and eustachian tubes. It is very important that he not get water in the ear which could damage the eustachian tube and middle ear. Trust me, he would HATE that. My middle ear and eustachian tube got damaged in a swimming accident 3 1/2 years ago. Ever since I have been plagued with very frustrating problems. I will not go into detail because I don't want you to get scared. He definatly should see a ear specialist. If the ear drum is badly damaged, he may need surgery. If it is only a small perforation, it may heal over the next few months. I hope you and your husband has the best of luck.