I am not sure if what you consider to be a mistake really is one. Anyway, if you feel that it is then yes all you need to do is ask the Lord for forgiveness and move on.( that is if that mistake does not involve an third party that might be affected by the mistake and is deserving of some explanation)...this could go a lot of ways. I wish you could be more specific.
all the best
If this was a big mistake you could ask forgiveness, if you have a pastor/ priiest how about you ask him , forgivness does help, and you have to forgive yourself, then yes Move On with your life.