The best treatment route for my hypertrophic breast/chest/cleavage scar? (photo)

Bad scar from tiny 0.5cm mole removal on breast. Had scar revised. Kept sports bra on 24/7 to prevent stretching/hypertrophy and got new thinner scar (pic 4). Went back to normal bra and scar stretched and thickened again - now 1 inch long, 0.5 inch wide. Looks worse to the eye. Had 1 injection and 1 laser treatment so far..very expensive. Just want a thin white line scar not this, it makes me feel sick and is visible with many clothing necklines. What can I do? Can't afford to waste £.