Skin update Bug HALP!!!!!!

[SilverTheAegian]

My skin updates fine on Vanilla 1.8, but it only updates my body, legs and head on 1.7 Modpacks, My arms have cool designs on the arms, I've tried getting rid of Avatar and Skin files in the .technic folder, I've tried logging out of every minecraft-used program such as forums, minecraft, technic, and updated it and left it for at least 2.5 days and that didn't work, It only updated my arms the first time I ever changed my skin on 1.7 modded, but never any time after that. PLEASE HELP!!!!