Hi Poh Ching Tan,
It is true that development of freckles is dependant on genetic factors and environmental factors especially sun exposure.
Even before considering treatment, it is important for you to avoid excessive sun exposure as this can aggravate the freckles and also increase the risk of recurrence if you go for treatment. Regular use of sunscreens will be helpful.
If your pigmentation is due to freckles, they do usually respond well to pigment laser treatment. It may generally take between 1 to 3 treatments but there is no guarantee that it will clear with a single treatment. Freckles respond well to IPL (Intense Pulse Light) treatment too. This has less down-time but may require more treatment sessions.
