Stretch marks on breasts 3 years post op - how can this be treated?

Dear nouhaila,
I understand your concern. However, without a proper assessment, it would be difficult to determine what is wrong. It is best that you visit your plastic surgeon for further assessment or ask for a second opinion. Only after a thorough examination, you can get proper recommendations and advice.
Daniel Barrett, MDCertified, American Board of Plastic SurgeryMember, American Society of Plastic SurgeryMember, American Society of Aesthetic Plastic Surgery

I would expect any stretch marks from the implants themselves to occur within the first 6m to a year. Fortunately this is quite rare but can happen if you're prone to stretch mark development. If you're 3 years out and have gained some weight and noticed your breast enlarging - I would assume the stretch marks are related to the weight gain. Weight loss and or implant removal could reduce the skin tightness.
Early stretch marks can be treated with lasers - halo and or BBL to help with the redness. It's impossible to get rid of them completely but ideally the treatments will improve the skin thickness, texture and color.

Your implants are no longer stretching your skin, but weight gain will. I suggest using Mederma for your stretch marks and consider micro-needling.