Little help with a rotation issue

I have a decal being placed on a object
The decal is made up of 4 different decals 4 on a texture map
So im setting the Tiling to find each decal.

The decal system I use assumes the decal is starting at the right rotation. It seems anyways.
I fixed this in the past by making the decal a child game Object and setting the x axis to 90 degrees.
so that offset it.

But I need to get this decal to work with not having a child object.

So my question is how do I add a x axis offset to a Quaternion. With out disturbing the hitRotation.

                    Quaternion DecaleHitRotation = Quaternion.(decal.transform.rotation * hitRotation);

                    DecalManager.Add(decal, collisionPoint + collisionNormal * 0.02f, DecaleHitRotation, (collisionTransform == null ? null : collisionTransform));

nevermind I got it. I guess it was as simple as * Offset