Will I suffer future harm, such as being deprived of progeny, as a result of masturbating 11 times in three weeks? Does lust cause harm to a person? And must I confess to my parents what I have done?

If your repentance is sincere, then know that the conditions for sincere repentance are: regretting the forbidden act, completely abandoning it, and resolving never to return to it. Among the things that will help you persevere in righteousness and abandon the habit are: supplication (Du'a), accompanying good people, staying away from things that incite lust, striving for marriage, or fasting if marriage is not possible. As for the future, do not worry about it, for "whoever fears Allah - He will make for him a way out." As for the origin of lust, it is innate in humans, and there is no harm in it as long as you strive to refine it. As for confessing to your father what you used to do, it is not obligatory; in fact, it is not appropriate. Whoever commits a sin should conceal it with the covering of Allah.