Hi sir....
The x_ray shows the cavity reaches pulp layer(nerve layer) which cause pain....
As the succedenous permanent teeth will erupt around 11_12 years,You need to go for pulpectomy (called as Root canal treatment in adults) followed by capping of the tooth....
Complications if you left Untreated:
The infection from the milk teeth will affect the underlying permanent teeth and retards its eruption
If you go for extraction of the involved teeth then the spacing will be closed by migration of adjacent teeth and cause dental crowding which results in inhibition of eruption of the concern permanent teeth
Next Steps
kindly visit nearby dentist for furthur consultation and management...
Health Tips
Avoid self medication....