You essentially have two things going on.
First, you really need to make sure that you are not scratching the skin following FX laser resurfacing. While you will probably heal just fine, if you injure the delicate new skin, you could increase the overall depth of injury and end up with long term scarring. Also, if you are itching more than usual, you might have an issue with either a light fungal or bacterial infection. These can be easily treated but if left untreated will delay your overall healing.
As for the redness, this may take up to a month to improve depending upon your skin type and the actual settings used for your treatment.
The best thing to do is to contact whomever actually treated you. Have them take a look and see if everything looks alright. Active FX resurfacing is a very safe technology but complications can occur. If they are addressed early, they can be easily treated and your long term results will still be very nice.
I hope that helps!