It is advisable not to do strecing of foreskin.
Thanks for your query.Based on the facts that you have posted it appears that you have congenital Phimosis
and want to strech foreskin by using some cream.
Please note that the Phimosis that you have is congenital in origin and can not corrected by stretching permanently.over stretching of the foreskin causes injury
to foreskin every time you attempt to stretch it, resulting into scarring and thereby thickening of foreskin.
The only proper treatment for Phimosis is to get circumcised .The surgery is very simple and carried out by General Surgeon
under local anaesthesia as a day care surgery and offers permanent cure.
Please consult qualified surgeon foe clinical examination and get circumcised so that you can have enjoyable sexual life in future.
Hope I have answered your query. If you have any more questions please feel free to ask me I shall be happy to help you .
Thanks and Regards.