Removing the glare in post processing can be very challenging. Your best option is to use a polarizing filter on your camera lens when taking the photo. In Lightroom, you can reduce the Highlights and Whites while decreasing the black point in certain areas with the brush tool or the radial filter, but this is the challenging part. If you have a really bright white glare on your image and you reduce the highlights, you may be able to recover some of the information, but it's more likely that your Bright White area will turn into a less bright grey area.