Is it permissible to masturbate to release accumulated semen without viewing forbidden things? And does the accumulation of semen negatively affect one after stopping masturbation?

Masturbation is forbidden by the majority of scholars, unless a person fears harm that cannot be averted except through it. Some Companions and Successors permitted it out of necessity, such as fearing fornication or illness. So, if a person fears falling into fornication or sodomy, or fears harm to their body, then there is no sin upon them. As for the accumulation of seminal fluid and its health effects, that is the domain of doctors.