Skin healing after being sliced off?

Hi there. I've been shaving my arms for years. A few weeks ago, I used a cheap razor that I wasn't used to and sliced off a chunk of my skin on my forearm. It bled for very long and was white at first. I'm really saddened about it because I have very tanned skin and it's still pink and fresh looking after 3 weeks. I have been covering it and applying mederma, aloe vera and neosporin to it a few times a day. My question is, How should I expect the scarring to look after this summer (a few months)? I had a similar thing happen to my leg the very first time I shaved, but that was 7 years ago. I can still see the scar, but it's the same color as my skin so It doesn't bother me. However, the area of my arm that was sliced is thicker skin and exposed to the sun more frequently. Is there anything else I should be doing at this point? When can I tattoo over it?