It is raised .It means some infection is there . Some chronic reactive infection. Mostly due to chronic cold cough , they have raised ESR.Never the less, do Mantoux test done and XRay chest.
Let me know or consult pediatrician physically.
Next Steps
take care of Nutrition with good proteins, vitamins,antioxidants and mi erals.
activity to be encouraged keep child socially engaged.and mentally challenged.
keep your child happy.Never abuse or shout or argue in presence of your child. They respond with mental behavior abnormality.