Can my breast grow after augmentation?

The answer is yes. Breasts will continue to change with time especially with periods of weight gain or weight loss. Besides that, implants will pull the breasts down and stretch the skin over the years and this can lead to a larger breast cup size. After four years it is unlikely to get sensation back to the nipple. This can be bothersome but isn’t likely to return at this point. Schedule a consultation with a plastic surgeon to explore your options. Hope that helps. 

It is certainly possible that any woman can experience breast enlargement during different times in their lives.  This is unrelated to your implants, as they are not growing.  Hormonal changes at weight gain can both influence breast growth. If you have not regained sensation 4 years after surgery, then it is unlikely that you ever will, unless you try some sensation training techniques.

It's certainly possible for your breast tissue size to fluctuate with weight changes after your breast augmentation.  Have you noticed a weight change?  Also, if after 4 years you still do not have sensation involving your nipple, it is not likely to return over time.