What will happen if I remove chin implant after 3 years?

 Hi, I have performed many facial shaping procedures, including Chin Augmentation with dermal fillers or silastic chin implants, for over 30 years.  In my experience it's very rare to be feeling numbness or discomfort 3 years post chin implant surgery.  Since your symptoms are on the left side, this might be an indication that the left side (wing) of the chin implant is near or pressing upon the left mental nerve.  You can confirm this with a 3-D scan of the face.  If this is a silastic chin implant, you can remove the implant and have your chin augmented about every 9 months using precise placement of a dermal filler.   I prefer using silastic chin implants placed through a small, curved incision under the chin as described below.  The sides, or wings, of the implants are placed on the lower edge of the chin to avoid making contact with the mental nerves. When the chin is weak, this creates an imbalance making the nose appear larger, the mid face top heavy, the lower face looks short, de-emphasizes the lips and allows early formation of a "double chin".  
 Proper placement of a silastic chin implant adds forward projection to the chin thereby creating harmony and balance to the lower face.  Using the same incision, liposuction can be performed to reduce the fat and further shape the neck.  Excess skin, from below the chin, can also be removed through the same incision.  
 I have found that placement of a silastic chin implant, through a small curved incision under the chin (also allows excess skin removal) to be very safe, quick, highly effective and far less invasive than a sliding genioplasty (requires extensive tissue dissection, bone cuts and placement of metal screws and plates to secure the cut segments of bone).  I perform chin implant surgery in 30 minutes or less, often using a local anesthetic alone.    
Hope this helps.