This may seem like a strange response, but...
Frankly, I've never looked for stretch marks. Now I know you probably didn't either, but there they are. I know I have some, but they just aren't the main focus in my life. I am SO HAPPY to have my cognitive function back, to have diminished pain and increased mobility... well, to me stretch marks are a small price to pay.
That said, I, too have read that some people have them go away, particularly if they apply the creams, etc like you have been doing. While with other people they never go away. I think it depends on a lot of factors, including but not limited to, skin tone, how long they were "plumped up" by the prednisone, overall age, speed of healing, all that stuff. Probably toss in some healthy eating, sleeping, and drinking lots of water in as well. I'd probably give it up to a year before I gave up -- while skin does regenerate it does take a while.
Best wishes, let us know how it goes!
Lynnwood, Lupus & Sjogren's Moderator, Dx: 2002DIAGNOSING LUPUS & HW's LUPUS 101
"Life is far too important to be taken seriously." - Oscar Wilde