Yeah, as Anna says. To test it, simply go to CAS and "equip" your sim with only the dress, nothing else. It could be that you added an accessory that is mapped on the same part of the uv hence having its texture overlapping on the dress. If it is fine with only the dress then it is what I described.
Also you can open the manage my CC feature of S4S to see if the dress is properly displayed on the preview.
Please do not contact me via pm for help and simply post in the appropriate section of the forum so that everyone can see and help you there.
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