I Accidentally Sunburned my Brand New Mommy Makeover Scars, Will It Go Back to Normal?

Almost every plastic surgeon will tell you to avoid sun exposure on the scars. What I have observed is that those who go to tanning booths often have the best scars. It may be because of the controlled skin damage that it causes and it makes the scars more lax. I never recommend sun exposure but for patients with the lighter skin types- it probably doesn't "hurt". In fact laser light treatments are often used to help scars. Dark skin types definitely can have darker scars with sun exposure. My guess is that the extra sun exposure won't hurt your result.

Sun tends to darken scars during the healing phase.  The darker brown color may last for many months, but eventually it should fade if you avoid sun in the future.

You certainly should avoid the sun after an operation. I don't see an indication for treatment with the laser if your scars healing properly otherwise.