It might be because the head is facing the wrong way, try turning it a little and moving the features of the face to the new front. It might also be because the decal was placed from the right side rather than the front. If those don’t fix it you might want to change it to scripting support so scripters can help you.
Can you set the Model’s PrimaryPart to another part that faces the correct direction?
I know Humanoids have a HumanoidRootPart, and that is the basis for the Character.
Is the main Part a Union? You could just Separate the Union until either the main Part or one of the Negated items is facing square to the XYZ axes of the Workspace. If you select a Negated Part first the whole Union takes that orientation so you could just make that Negated Part face ‘forward’ then select it first when remaking the Union. Or you could just add another Negated item outside the Union with the correct orientation and select it first, then Union both.