On the contrary, computer science degree programs only make you more marketable and add to your current skill-set. In fact, as asserted by the National Association of Colleges and Employers (http://www.naceweb.org/Press/Releases/Top-Paid_Majors_for_the_Class_of_2011.aspxas asserted by the National Association of Colleges and Employers), the salaries for Computer Science majors are among the highest right now, averaging at $63,017.
Even if you already possess the skills and expertise required by a computer programmer, the stamp of a computer science degreecomputer science degree from an accredited college will give you something to show for it.