Call 911 for medical assistance as soon as possible.
The following are things you should check when you attempt to give aid to a victim of lightning:
Breathing - if breathing has stopped, begin mouth-to-mouth resuscitation.
Heartbeat - if the heart has stopped, administer CPR.
Pulse - if the victim has a pulse and is breathing, look for other possible injuries. Check for burns where the lightning entered and left the body. Also be alert for nervous system damage, broken bones, and loss of hearing and eyesight.
Source: Federal Emergency Management Agency (FEMA)