I want to ask if someone had done a Musharata to himself telling Allah (swt) to forgive him, that musharata being that he will recite Namaaz Shab for a week and if he did not do it what is the consequeses or what should he do?

If you are referring to nadhr then it’s not permissible to break it. If it’s a qasam (swearing) then breaking it would require paying kaffarah which is to feed 10 needy people.