Do I have to wear internal corneal shield when I get co2 fractional treatment?

For safety sake you should wear the internal eye shields when lasering in this area. The external shields can slip or move and a stray shot from the laser could create a burn on your cornea. The eye shields are very well tolerated as typically numbing drops are used before they are placed. If you were lasering the cheeks or forehead, the internal shields could be avoided but for your area in particular I would use them.

This question speaks to the comfort-vs-safety issue. Internal shields certainly provide the maximum protection - especially if the treatment is going to be used right up to the rim of the eyelid. Other metallic occlusive measures, however, may be adequate for laser application not right up to the rim.  Your treating physician can best advise you with the level of precaution required for your treatment. I love fractional CO2 laser for improving fine lines around the eyes and mouth - it is effective and reliable. Downtime, however, may be an issue as the redness, swelling and tiny scabbing may persist for a week or more.  Hope this helps!