Thank you for asking. Having excess of foreskin is normal. However, if the foreskin is very tight and prevents smooth retraction onto penis shaft, then it is a concern. If while erections, the skin is not getting completely retracted, then you are likely to be having a condition of Phemosis. In such a case, it's needs to be corrected from a general surgeon.
Next Steps
Kindly show yourself to a general surgeon. He can conduct a detailed physical examination and assess the severity depending upon which the management can be decided.
Health Tips
Don't worry. It is completely treatable.