I cannot promise you a complete restoration of the pigment. Lasers work by heating up the skin and that sometimes results in destroyed or impaired function of melanocytes (pigment producing cells).
I recommend you a regular 0.5 mm dermaroller (roll up to three times a week). If you feel that your hyperpigmented edges are getting worse after dermarolling (temporary redness or darker skin is normal), buy a 1 mm dermastamp and stamp only the depigmented skin (do not touch the hyperpigmented edges).
Concerning the stretch marks, if you do not have way too many, you should buy our single needle (we soon have them in stock) and needle only the stretch marks.
When the skin is healed from microneedling, expose your hypopigmentation to the sun because melanin is produced as a reaction to UV (provided there are melanocyte cells in the area to produce it). When you are going to tan your hypopigmented areas, apply a high factor UV cream just to your hyperpigmetnation. You can apply it for example with a small cosmetic brush or use those cotton sticks that are sold to clean ears. Or buy a baby diaper rash cream containing zinc oxide and apply a lot to the hyperpigmented areas prior to the sun exposure. Zinc oxide reflects the UV. Your hypopigmentation needs sun and your hyperpigmentation must be protected from the sun. I know it is not easy..
For the hyperpigmentaion, continue with Tretinoin.