This phase II trial tests how well EMLA topical cream works in treating pain in patients with skin cancers receiving Technetium 99 injections for a lymphoscintigraphy mapping procedure. A lymphoscintigraphy mapping procedure is used to find the main or lead lymph node (tissue that fight infection) so it can be removed and checked for tumor cells. Using lymphoscintigraphy to highlight and then surgically remove lymph nodes is standard way to treat skin cancer for many patients. The Technetium 99 injections used for lymphoscintigraphy can be briefly painful due to the sensitivity of the nerve endings in the skin. The EMLA topical cream, which contains a numbing medicine to block pain from nerve endings, has been studied in breast cancer patients with a difference in pain reported, but this is the first time it has been studied in patients undergoing lymphoscintigraphy for skin cancer. This study may help researchers learn whether the use of EMLA cream may improve the associated pain at the time of the lymphoscintigraphy procedure.