What you did is far from a prank...you betrayed his trust, invaded his privacy and misrepresented him to the public. Apologizing is not enough. You can't just apologize and move on. You have to be responsible. You have to clean up your mess. If your dog takes a crap on someone's lawn, do you just apologize and keep walking? Don't you think you have a responsibility to pick up YOUR dog crap?
So the question is how do you make up for the harm you did? Well they say time heals all wounds so give it a little time and then do something genuinely considerate for him. Maybe buy him tickets for two (not for you and him though) to a concert, give him a gift card, you know him, figure out what he'd like or could use and give it to him as a token of peace. If his friendship is of value to you, right your wrong and you will be friends again or else you are sending the message that his friendship is not worth anything to you, except maybe a laugh at his expense.