The pain caused by the insufflation of drugs can range, depending on the substance and dose involved, from a light tickle, to the metaphorical punch in the face logicism took from Goedel's incompleteness theorem. There are some simple measures you can take to reduce the pain caused when you insufflate a drug:
Additionally a simple method, known as nasal irrigation, can be used both before and after snorting a substance, to help clear the nasal passages and reduce pain, as well as damage to the nasal cavity. This guide will explain how to create the solution and how to use it.
Typical saline solutions are comprised of your most basic household goods: water and table salt. The typical solution has 9 grams of table salt per 1 litre of water. You can create this simply by mixing the salt in with the water in some container (such as a bottle of water), and then mixing it, until the salt has dissolved into the water. Be sure to label the container clearly, stating on it that it is a saline solution, and that it should not be drunk (also: don't drink it), as well as its concentration. Creating a solution such as this is a form of volumetric dosing, about which you can find more information in the Quick Guide To Volumetric Dosing.
This method can be used to reduce the pain caused by the insufflation of a drug both before and after dosing, and becomes particularly helpful when one is redosing with a particularly painful drug. First transfer some of your saline solution to a smaller container. The container should ideally be something which will allow you to 'squirt' the solution. However, if this is not in any way possible, using the lid of a drink bottle and carefully pouring the solution into your nose is also okay.
To perform the irrigation, repeat the following procedure for each nostril: hold the container to your nostril, holding your head upwards, then gently squirt the solution into your nose. Aim the solution toward the back, not the top of your head. The solution will run through the nasal passages and into the back of your throat. Spit it out through your mouth. It is not dangerous to swallow a small amount of the solution.