It looks like metal exposure of the crown and the discolouration of gums is probably due to leaching of metal caused due to the exposure. Gums are in healthy condition though, no signs of inflammation. If it’s not bothering you in anyway other than cosmetic reasons, then nothing to worry. And if you are concerned about it, then you can visit your dentist and go for another crown (eg Zirconia).
Next Steps
Visit your Implantologist and get a follow up IOPA X-ray done to check the condition of implant and the bone surrounding it and replacing the crown if need be.
Hope this was helpful.