Nothing to worry. Most probably due to gingival inflammation.
Pls follow these for maintenance of oral hygiene and until you visit dentist for a scaling and polishing to teeth.
1.luke warm water salt gargle few times per day.
2.brush with correct technique gently with soft bristled brush, after meal, twice a day.bed time brushing mandatory.
3. Mouthwash: clohex plus.take 2-3 ml directly in mouth,, once every 2 days, after meal.donot eat drink or rinse mouth for next half an hour.
Next Steps
visit dentist get a thorough scaling done
Health Tips
quit if you have tobacco chewing or smoking or alcohol consumption habit,no betal nut or quid or pan masala khaini gutkha as well.