I had laser treatment for thread veins on my nose two days ago and have now developed large scabs on either side of my nose.

The lasers used for treating spider veins targets the actual pigment in your blood to damage the vein.  Depending on the settings of the laser varying degrees of redness and even blistering can occur.  This usually heals very nicely as long as it does not get infected.  There is a cream called Silvadene that is very good for these types of wounds but requries a presription.  At this point, I would recommend showing your nose to your treating physician for further advice on caring for it. 

At this point, 2 months out, you could use a product from Plato's Medicinals called Scar Serum and apply on the areas where you had the laser injury/treatment and this will optimize healing. 

Laser is essentially a hot light and heats the tissue at a specific wavelength.  This can result in an are of blistering which is a localized burn.  Topical treatment as you are doing usually solves the problem.  There are many options for topical creams and ointments and if you do not see improvement by one week post treatment then you should follow up with your treating physician for reevaluation.