Cocaine blocks the re-uptake of all of your neurotransmitters, but it has a certain love for the dopamine pathways in your brain. Since the nerve terminals in your brain can’t get rid of all of that neurotransmitter in the cleft, especially in the mesolimbic reward pathway, you feel euphoric. The other neurotransmitters that aren’t taken back up lead to the other symptoms: increased heart rate, energy levels, blood pressure, agitation, etc.
Perforated nasal septum due to cocaine use. When cocaine interacts with nasal tissue it forms hydrochloric acid. Given enough time it will dissolve the mucosal tissue.