A cheek cell is a eukaryote, also known as a eukaryotic cell, as it come from mammals which are animals which are in the domain Eukarya. Eukaryotes and prokaryotes differ in many ways. Eukaryotes have true nuclei (DNA with nuclear membrane) and membrane-bound organelles. Prokaryotes lack many organelles, none of which are bound to the membrane. Eukaryotes appeared much later in geological history and are about 30 times larger.
The word prokaryote is interchangeable with the word bacteria. Because sperm cells are not bacteria, it is not a prokaryote, but a eukaryote. In a more complex answer, you cannot make prokaryote from a eukaryote, because sperm cells are made from a eukaryotic cell. That's like saying that your fig tree grows peanuts.