The gum around my implant looks dark. Is it okay to leave it?

If the gum is thin, the metal abutment connected on top of the implant may show through. If you are concerned about appearance, options include replacing it with a tooth-colored hybrid abutment, but each option has pros and cons—please discuss with your dentist.
For gingival health, the abutment is sometimes intentionally exposed slightly above the gum line, in which case the abutment may appear dark.