Can a hypnotist or psychiatrist help you keep bad memories repressed?

No: At least, i've never heard of it.

Find meaning: I'm no psychiatrist, but i understand that all mental healing includes your choosing what the terrible things that happen to you will mean to you. We learn from the worst as from the best -- if only perhaps that we do not want others to experience what we did, and be alert in helping and protecting others. "the best grapes do not grow from the best soil." embrace life's experience & love others.

Use Caution: If you study memory is, it can be thought of as process where there is a mathematical probability of a certain group of neurons firing off in a certain order at a given time. Research on memory shows it is very imperfect and is altered every time it is pulled into active consciousness. Thus, great caution should be exercised with hypnosis and with therapy when retrieving "repressed" memories.

Supression: Repression -no. That is an unconscious defense mechanism. However, there are times when i encourage a patient to suppress a memory. This means making a conscious choice not to deal with the upsetting memories at that time. If the person is unraveling fast (regressed & in crisis) delving into painful past events may destabilize them more. In this case, i would encourage them not work actively on.