I think alpaca is supposed to be hypoallergenic, but you never know. I'm sure some people are allergic to it and maybe you're one of them. Taking an allergy medicine such as Claritin or Benadryl might help keep your symptoms at bay, at least temporarily while you're knitting.
There is no right way to knit; there is no wrong way to knit. So if anybody kindly tells you that what you are doing is "wrong," don't take umbrage; they mean well. Smile submissively, and listen, keeping your disagreement on an entirely mental level. They may be right, in this particular case, and even if not, they may drop off pieces of information which will come in very handy if you file them away carefully in your brain for future reference.