Probably not; the audio options inside Camtasia are rather limited. Hiss is usually continuous underneath all voice sounds. If it's affecting the 'S' sounds only this is usually referred to as sibilance.
Do you still have the original track somewhere as it was? Can you still do an UNDO on the volume leveling process? Depending on the original issue, there are multiple methods to improve an audio track outside and then bring it back into the project.