Hello from one user to another. Raised in medical family, I’m not a doc but hears a good guess.
Smoking crack ( again I do it so no judgment) is hard on the lungs and throat. I’m sure you know this. You can reduce the effects some by not chasing that last hit that isnt there and torching your wind pipe. Heavy smoking anything will cause lung damage and throat problems. The crack isn’t making your cough better per se but the immediate effects are a numbing of the throat and lung tissue so that your body is under the affects of a cough suppressant. After the numbing wears off you will go back to coughing albeit with a little more damage and buildup of things you don’t typically want in your breathing apparatus. The only good thing to do is space out smoking more ( less frequently). Good luck.