Has my honor been lost after my brother sexually assaulted me when I was ten years old, and that continued for four months, despite my repentance and commitment to the obligatory duties? And what should I do now? Should I go to the doctor?

Adultery is a major sin (kabirah) and its punishment is severe. The sin is compounded if it is committed with a mahram (unmarriageable kin). Whoever falls into these sins must conceal himself and not inform anyone. Those who repent, believe, and do righteous deeds are exempt from the multiplied punishment, for Allah will change their evil deeds into good deeds. A child who has not reached puberty is not held accountable for their sins. If the act occurred before puberty, there is no sin upon you. If it occurred after puberty, and you regretted it and repented, then your sin is forgiven. Treatment is permissible if the hymen was broken due to a cause that involved no sin.