Ouch this is pretty brutal if true. I honestly don't understand how you thought this wouldn't hurt his feelings and break his trust towards you. There's a chance he may forgive you, but thats not without some emotional scares and/or lack of trust towards you.
I'd say let the guy cool off for some time, try to apologize, try to make amends, but don't try to force it.
Maybe Promise to not do any more pranks on him(?).