Yourself. Your deeds show who you are, or in other words - actions speaks louder than words. If you do feel, genuinely, that you need to seek forgiveness, then from the person whom you have offended. You don't need to seek false forgiveness out of a false sense of false duty every Sunday from a person who can't possibly absolve you of your "sin" after you have offended someone else.
If you have offended a Daemon or Daemoness, for example, then... well... Gods/Goddesses help you and the best of luck! Making it up to the offendee, I would expect which would be on their terms, not on yours, would, if they decide, be sufficient - as long as it is to their satisfaction, of course. This person could then take advantage of you. It is also important to know that being sorry too much leads to you being weak and cursed easily, so you have to decide if you are to be sorry for a misdeed or not, if it has offended someone or not.
Be careful about being arrogant and/or meek, over-confident and/or a pushover, having superiority syndrome and/or inferiority syndrome. As a Spiritual Satanist, you are superior, but you don't have to be a stupid bitch about it. As a Spiritual Satanist, you can understand things more so have more sensitivity to matters and problems, but you don't need to be a little weakling about things.