Hi, Hope you are doing great. Garlic can cause contact dermatitis. Sulfur molecules like diallyldisulfide, allicin, and allylpropyldisulfide in garlic are thought to be the principal offending agents. These components appear to be heat sensitive, so raw garlic causes skin reactions that resemble like burns. Since you mentioned you had acne, that means your skin is more sensitive than others. On top of that, application of raw garlic made it worse by causing a chemical burn. When the burns healed they left behind scars. Meet your dermatologist and follow his advice. Depending on your scar type, whether they are pigmented or tiny pits, he/she may prescribe you retinoids, glycolic acid, Vit. E, silicone creams, sunscreen,etc. You may also benefit from chemical peels, microdermabrasion, microneedling and lasers. Take care and happy new year.