Is there a way you can forget about someone by using Prayer and Hypnosis Therapy?

I think you hit the nail right on the head, ask God for the strength to focus on things other than this person. Ask Him when you get up in the morning, when you go to bed at night (also thank Him for giving you said strength) and anytime you feel like you can't focus. It may take a little bit, but even taking a minute to pray will distract you and then God will help you the rest of the way. Just make sure you are asking humbly and with faith that He will help you. Good luck.