It is necessary to apply to the police with a statement about the commission of a criminal offense.
The investigator will issue a decision on the appointment of a forensic medical examination and you can apply to the forensic medical examination office (you must have medical documentation with you).
In the case of entering information into the Unified Register of Pretrial Investigations (violation of a criminal case), the investigator (investigator) will remove medical documentation and, on the basis of medical documents, appoint a forensic medical examination (of course, this is possible if you turned to a medical institution for help).
As such, there is no term of appeal - it is limited to the statute of limitations (Article 49 of the Code of Civil Procedure). The best option is to undergo a forensic medical examination immediately and then attach the medical documentation, because if you have only visible injuries, they may disappear over time, and the doctors of the medical institution may not pay attention and may not include the presence of, for example, a bruise on the hand in the medical documentation.