What Does Growth At Appendix Removal Site Indicate?

My 18 year old son had his appendix removed by key hole surgery on 1Nov 2014. He recovered well with no complications. A few weeks ago he noticed several small growths (15-20) around the scar areas that look a little bit like warts but are smooth. He has no pain/itch but they are not nice to look at. Do you know what they might be and what he can do to get rid of them thanks?