Is going to the doctor embarrassing because of a small penis, knowing that marriage is approaching?

For this type of operation or treatment, there are two scenarios: First, if the organ is performing its natural function, it is not permissible to change it, as this falls under altering the creation of Allah, the perpetrator of which is cursed by the tongue of the Messenger of Allah, peace and blessings be upon him. Second, if the organ has an acquired or congenital defect that prevents it from performing its natural function unless treated, then there is no objection to treating it.