Could anything besdes breast cancer cause dimpling of breast skin?

Yes, but...: Every new finding needs to be considered as the most serious treatable illness until proved otherwise. A single large new dimple may be the result of injury and scar contraction, but you'd do well to have it seen in any case. The familiar orange-peel effect is also very concerning and should prompt a physician's office visit. If you have either of these, please seek evaluation without delay.