WOW.....Listen I don't want to sound like the bad guy so I'm going to go about this nicely.
1. Your linework is extremely shakey, and inconsistent.
2. Your colorwork/fill has more holidays than the U.S calendar.
3. Your going way above and beyond your limits.
You need to slow way down, and crawl before walk. Get some fruit and practice your lines first, until you have a nice solid consistent lineweight. Once your confident with this, "Do it some more". Then post pics of your outcome and let us critisize/appraise that before you move on. I know you want to go at it balls to the wall right off the bat, but it's permanent. The bad thing is, your girlfriend now has to walk around with a less than stellar tattoo (that can be fixed) because you jumped the gun. You now have to walk around also with a tattoo that isn't up to par (also can be fixed). You tried to cover an old tattoo, and went about it the wrong way. Cover-ups aren't about going over a tattoo with a larger darker tattoo. It's about creating an illusion. It's about averting the eyes away from the old tattoo with a new focal point. For your sake, and others, slow down and start with small basic solid fill designs. Make sure they are solid without overworking the skin. Study and learn where you went wrong, and how you can improve...