Thanks for your query. stretch marks are very difficult to treat. You can go in for co2 fractional laser or microneedling once your lactation period is over. For further information you can consult medpsa

Once a stretch mark always a stretch mark. A stretch mark is a permanent damage to your dermis. It's unfortunate but true. All that you have tried were not sure shot preventive measures neither are they approved treatments. All I can reassure you is that they will fade and become close to your skin color. But there will always be a residual mark present. Regarding your lax tummy... that goes down with wait loss and abdomen exercises. But please remember, it doesn't 'flatten' out. Ideally, visit a dermatologist for a one on one discussion. I'm sure a personal meeting with a dermatologist will be far more reassuring than 'reading ' an answer like this.