ouch, that's a tough one!
well, from my own personal experience,the only thing that I've found to help cover them a little bit, is using make-up, like foundation. it's a pain in the *** to apply everyday, though. You could always say that you've worked in a restaurant, and they are burns from cooking; grease splashing, burnt from the oven and so forth.
as for not being able to tell your family, i understand 100%. since telling my BF about it, he refuses to talk about it, and acknowledge it, therefore i have to hide it from him.
unfortunately, a lot of people assume suicide when seeing SI scars. that's something that I think will change over time as it becomes more prevalent in our sociey and people learn more about SI itself.
congrats on being in recovery;we all know how incredibly difficult it is to fight those urges