Though I do understand the previous comments telling you not to, I also totally understand why you wanna cover it up. Sure, its a part of you and your fiance loves you just the way you are - but its like getting your hair and make up done for your special day! It just makes you feel extra pretty on your big day - even though you know your husband is going to love you just as much when you wake up beside him the next morning with messy hair and no make up.
If you decide not to cover it up and are comfortable with that - good for you. If you feel you'd like to have it covered, I'd recommend stage make up, which I use regularly to cover the hemangiomas on my arms and shoulders. Actually I recently wore an strapless gown to a ball and had all my birthmarks completely covered with stage make up. Its the same sort of make up used to hide tattoos on actors etc.
It CAN be a bit tricky to apply especially if you're not used to it, so if I was you I'd get it done by a professional make up artist. But it can definitely successfully be done if that is what you choose to do.