I know that there are various stretchmark creams on the market but I don't know how effective they are. Many of them offer a money back guarantee if you're not satisfied so you may want to go that route and then return them if they turn out to be junk.
I developed quite a few stretchmarks over the years, especially around the chest and shoulders. I tried cocoa butter, but that didn't really do anything. Good news is they do fade a lot over time and tanning will make them less noticeable.