Good thing you asked. I hope you will listen to what is being said in this thread, otherwise you're doomed.
I don't mean to sound dramatic, but please consider the following.
Stimulants will raise your body temperature. Some do it better than others. If your blow turns out to be cut with speed, or even caffeine, your temperature is going to spike.
The seriousness of your fever depends on what is causing your infection. The body tries to fight infection by raising your body temperature. However, your brain has a natural limiter and in most cases it won't surpass 108F. I don't know how cocaine or any other stimulants might effect this limit. Anything above 108 for any prolonged period of time is going to cause serious brain damage.
Cocaine is generally unsanitary. A lot of the time it sees moisture in one way or another, when it's produced, pressed, cut and bagged. It's then sealed and kept at room temperature. This is the Cancun for bacteria. As you may very well know, cocaine is corrosive, and it will break down the first layer of our body's defense (our skin). Normally this is not too much to ask of our immune system. But, the fact that you have a fever means your immune system is compromised with an existing infection. The added strain of cocaine, which in itself raises your body temperature and puts additional strain on your circulatory system and heart is a recipe for disaster. Keep in mind that your circulatory system is the most effective way that your body keeps you cool.
If you do get too hot, and a cold shower isn't possible, you're going to want to protect your brain. One good way of cooling your body is to wring your wrists in cold water. It is more effective than drinking cold water. It works because your blood is closest to the skin around your wrists. The blood circulates very quickly and will bring your temperature down. A very high temperature is going to land you in the ER. Anything over 105F earns a visit. Keep in mind that NSAIDS (like Tylenol, Advil) may only lower your temperature by 1 or 2F. More than likely you'll end up in an ice bath. I had to get one once as a child. Let me tell you it fucking sucks. But it's either that or brain damage, possibly death if not treated right away. The false sense of well-being from the cocaine is not going to help you realize when your temperature is in the danger zone. It's your choice if you want to put yourself in such risk, but at least consider what you're up against.