Ticks are definately NOT white. Ticks are black or brown(maybe dark red). Mites are black or brown(or dark red-blood engorged). The only white parasite I know of are lice, and I am pretty sure snakes don't get lice. The white flecks just may be her pattern or something else in the enclosure.

If you believe she has a cold, what are you seeing/hearing? Does she have bubbles coming out of her nose or mouth? Is she wheezing loudly every so often or constantly? Or is it a very low, quiet wheeze, every now and then? Sometimes snakes will make some noises when they are in shed. The loose skin makes a whistling when they breathe through their nostrils. Is she lethargic? When you take her out, does she always feel cold to the touch? (not cool, but cold).

What her temps and humidity are and how they are being provided to her are very important to the snake's wellbeing, health and immune system. Not providing proper temps(or inaccurately measuring them) can cause the snake to get sick. It takes a long time for a snake to get visibly sick, and when you start seeing these signs, the disease has usually progressed to a stage that may or may not be successfully treatable.

Please get the snake to the vet and save yourself, and the snake, alot of trouble(and perhaps heartbreak). Treating a respiratory infection early is very important so it won't come back over and over again.