Sudden change in feeling at 4 years post op - should I be concerned?

I am 4 years post op, with Polytech Round 545CC implants, over the muscle. I have recently been trying to lose weight and lost around 5Kg, not enough to cause a major change in my implants I would think. Over the last 5 days, I have noticed a funny feeling in my left breast. It is not painful or hard (when resting or doing exercises) but I feel like the skin by the left side of my nipple is pulling. 5 It is closer to a numbing feeling that is just always present. No change to shape either.