The truth is there are no medical treatments available with zero potential hazards. IPL hair removal and laser hair removal are no exception. The side effects involved can be temporary (15min) or long term (months, years or even permanent). I also categorise side effects into common and rare.
Sun exposure can lead to exaggerated sunburn, which can lead to inflammation and post inflammatory hyperpigmentation, which is darkening of the skin in the areas treated. It may take months to go away. People with olive or darker skin complexions are especially prone to this condition.