Fork Dust Seal

The dust seal has slipped down onto the inner tube of my clutch side front fork. I assume it's a dust seal-it's a white plastic ring about 1/4" wide. What's involved in fixing/replacing it? Does it need to be done soon? Thanks.

I thought it was a brace for the dust seal but according to my mechanic it's just a spacer that serves no important purpose.

my definition of a spacer is something that sets end play or to keep components apart. on my classic which is different from r3t you have the fork seal, a retaining ring and then you have the dust ring that you just push in with your fingers.
if that is the dust shield you might put a small amount of silicone and push it back in.
in the regular manual it shows on page 14.2
the bushing, then the fork seal, a retaining ring and then you have the dust seal (CLASSIC)