Question about the tattoos

Rating: 9/10 (1 August 2001)

Have to say it, the movie is one of the best movies I ever saw. I rated it a 9. **** DON'T READ THE FOLLOWING IF YOU HAVEN'T SEEN THE MOVIE****

In the end of the movie, when Leonard tries to think back, you see a snapshot of him in bed with his wife. She's laying on his chest but the thing is - he's tattooed already. I don't get it. I'm probably not supposed to either, but can't stop trying. Is the scene just a mix of his memories - or the memories he thinks he has? Or did he start tattooing himself before she died? But then the tattoo about John G raping and KILLING his wife doesn't make sense. Any ideas?
Thoughts or ideas about this will be appreciated...