Lack of proper cleaning of teeth and gums leads to swollen bleeding gums. And when you are a smoker, the inflammation increases further. Other readons of bleeding gums are
diabetes, misaligned teeth , bab bites etc.
Next Steps
Get a professional teeth cleaning(scaling) done by a dentist. If required, dentist might suggest you to go for root planing and currettage if scaling is not enough. Use a gumpaint containing astringent. Maintain brushing twice a day.
Health Tips
Use toothbrush with ultra-soft bristles.