I think a headache caused by an ill fitting helmet is a safety concern and should be remedied. A person would be thinking about their head as opposed to negotiating the road. However, suggesting that a person should fix this by compressing sections or otherwise modifying the protective part of a helmet without knowing what the real effects are bothers me. At what point do you stop? Whatever you did to your helmet was probably very minimal and it's your own deal anyway, I can't tell you what to do, but encouraging others to this seems strange when there are better options. Also, when a helmet breaks in, it is not the protective foam that changes, it is the padding/liners. Those serve very little use in the event of a crash, only there to make it feel good until you use the other parts of the helmet. The OP was up for getting a new, properly fitting helmet. I would encourage him to do that and keep the HJC as a backup or for a passenger.