what can be done with stretchmarks is to lighten the appearance or to tone it up and make it firmer.
there are people who go for expensive radio frequency treatments that can be costly and gives hot sensation on the skin. There is also galvanic treatments which uses low current energy to treat the skin and make it firmer and make it more toned in appearance.
as for creams, there's a lot in the market, you have to find one that has proven clinical studies and you have to see if the mechanism of the ingredient will really give the affected area the firmness that you want.
pls refer to our thread on how to get rid of cellulite for more discussion on this as stretchmarks and cellulites almost have the same issues.
Hope this helps.