Can chemo change your dna profile?

Not really: Chemotherapy can cause some damage to dna but it is usually difficult to detect and it is quickly repaired by the defense mechanisms that normal cells have. Cancer cells lack such repair capabilities and as a result can not repair the damage and are eliminated via a process called apoptosis( also called programmed cell death).

Theoretically.....: It first depends on what what you were sampling to determine the profile (blood versus cheek cells vs semen). Dna profiling examines extremely polymorphic (varying) regions of the genome. If the chemo caused a dna change in a primitive stem cell in your body in one of these locations, it theoretically could affect a dna profile. Fun thought experiment, but super unlikely.