It’s called paronychia ( a bacterial or fungal infection of the nail/nailbed) .if left untreated can spread to the entire toe and will be extremely painful.
Swelling, redness, pus formation and pain are few of the symptoms.
Causes can be unhygienic pedicure, frequent moisture exposure , ingrown nails
Next Steps
Please consult your doctor and get it treated at the earliest
Health Tips
Maintain hygiene, apply proper medication on the affected area.