The bleeding may be due to a gum infection, or it could be caused by decayed or infected teeth leading to infection and bleeding. You should visit your dentist for a proper diagnosis so that appropriate treatment can be provided.

It might be because of following possible reasons...... 1.decayed tooth causing infection in the tooth and surrounding areas Or 2.gum infection causing the bleeding from  gums

Bleeding while brushing at night from left 1st molar area in a 6-year-old is very common and in most cases it is not serious, but it needs in-person check-up as you have planned. Most common reasons at 6 years age: 1. Eruption Gingivitis of Permanent 1st Molar: At 6 years, the first permanent molar erupts behind the milk teeth. The gum over it is swollen, fragile and bleeds easily while brushing. This is the most likely cause as per your description - bleeding started a month back, stopped, and came back now. This matches eruption cycle. 2. Decayed milk tooth / gum infection: If the tooth is decayed, food lodgment causes gum infection and bleeding on brushing. 3. Plaque accumulation / improper brushing: Vigorous brushing at night with hard bristles can cause bleeding. Next Steps - Please check and tell your dentist tomorrow: 1. Is the bleeding tooth a new big tooth coming at the back (permanent molar) or a milk tooth? 2. Any cavity / black discoloration / food lodgment in that tooth? 3. Any pain while eating, swelling, bad breath? 4. Any habit of hard brushing or any cut due to sharp food? Your dentist will need: • Clinical examination of that area • If needed, a small X-ray (IOPA) to see if it is permanent molar erupting or milk tooth with infection Helpful Tips till you visit tomorrow: 1. Don't panic. Avoid hard / vigorous brushing at that spot. 2. Use a small, soft bristled kids toothbrush with pea-sized fluoridated kids toothpaste. 3. Ask her to rinse gently with plain water after brushing - avoid forceful spitting. 4. Avoid sticky chocolates / biscuits at night before sleeping. 5. Don't try to pick that area with finger / toothpick / home remedies. In most 6-year-olds this settles after proper cleaning and eruption is complete. Please get it examined in person tomorrow and share the dentist's findings if you need a second opinion. Hope this helps. Take care of your little one.

Hello. It is difficult to comment without clinical examination in this case but as per your description it seems that bleeding is from the gum over the last tooth. You should get a regular check up done so that it can be analyzed