Two kinds of skill
Self-declared — you added it. It says what you believe you can do.
Verified — the platform observed you doing it, in an interview, an assessment or a coding exercise, and recorded the evidence.
Nothing you can do from your profile turns the first into the second. That is the point: the marker is worth something to a recruiter precisely because it cannot be self-awarded.
How verification happens
When an interview is scored, each skill it examined is scored individually. Where you demonstrate a skill well enough, it is recorded as verified with a level and a link back to the evidence — the question, your answer, and the reasoning.
A skill you performed poorly on is not marked verified, and it is not marked as a weakness on your public profile either. It simply is not evidence.
Progress over time
Skills verified in different interviews accumulate. Sitting a second interview that examines the same skill updates the record rather than duplicating it, so a skill you have improved at shows its current level.
What recruiters see
An organisation interviewing you sees the skills you have verified with them, and your self-declared profile. Verified evidence from another organisation's interview is not shared across organisations.