Self-examination may sometimes be confusing. Please get your friend to visit a doctor immediately. It usually starts with a little lump that feels hard, but can take many forms such as a mole or an indentation. Honestly, even if it is harmless, there is no harm in visiting a doctor and being at peace. I hope it turns out to be a false alarm.
Also, if you think you don't have the time, please try out some online research. Some specialised hospitals provide online technology to help you determine if you should visit the doc. I know of Manipal Hospitals that integrates Watson technology for this. If, for any reason, a doctor's visit is not possible at the moment, you really need to try this and get specialist opinions.
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