Enjoy, In some of the forums people have had success using a conductive circuit writer pen to build charge terminals back up to work good again.
Samsung Gear S replace charge connector, link below shows tear down of watch at which point you will be able to access charge terminals and possibly replace, may have to desolder and solder new.
Check the attached links,instruction and guides, Good luck
I hope this helped you out, if so let me know by pressing the helpful button.
[guide|50495]
https://www.google.ca/search?q=circuit+writer+pen&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiUxdfz3KbPAhWJ3YMKHSErAakQsAQIQw&biw=1024&bih=681