Thanks for the query.
You should not left the tampon inside for long period, because that can lead to infection many times.
According to your description there is possibility of some vaginal infection
and inflammatory reaction.
You better consult gynecologist once again and get examined local and the swollen areas.
Go for vaginal swab culture and sensitivity and complete blood picture to rule out the possible cause for your problem.
Meanwhile you can use local antibiotic
and anti-inflammatory cream for symptomatic relief.