Here are some pointers from an article on what to do about stretch marks/stria:
Soothe the skin. There are a number of creams and oils containing various ingredients such as alpha hydroxy acid, cocoa butter, vitamin E and plant extracts that may help get rid of stretch marks. While their efficacy may vary from person to person, and the products are sometimes costly, their use is probably not harmful. Check with your doctor to see if they may be worth trying in your situation.
Medicate. Your doctor may prescribe a topical retinoid cream to help remove stretch marks. Sometimes topical steroids may be used in combination with other creams or ointments.
See a dermatologist. Skin treatments such as laser therapy, microdermabrasion and chemical peels can help, especially if the stretch marks are relatively new.