Re: insurance specialist help!
You need to get a so-called Accident Number ("Unfallnummer"). That's the real door-opener.
To get it, you might have to go round in circles a bit, at first. You ask your doctor for one, and he/she might say that issueing the Accident Number is the job of the medical insurance. Then you ask the medical insurance and they might say they need an accident report from the doctor. Such a report does not have to be a Medical Report ("Arztbericht") but merely a registration, by the doctor, of the accident ("Unfallmeldung").
Sometimes, the doctor or the medical insurance may tell you to do this yourself, and you can download a form on Helsana's website. There, give all the dates and times, policy numbers, names and addresse, etc. buuuuut.... describe the accident in very few details, so no-one can later diminish your benefits on the basis of some phrase you innocently use.
All that I've written here applies just as well to the rounds you might have to go through with the HR department at your place(s) of employment, if you are employed, or with SUVA, where your employer should have insured you, or with any hospitals which are/were involved in the treatment. Hospitals are supposed to report accidents automatically, but do not always do so, largely because they lack the staff to keep phoning around.
The thing to do is to persevere until you have an Accident Number. It may take you a lot of phonecalls. Collect all names, direct phone numbers and email addresses along the way, and note the dates of your contact..
If you meet with a "no" at every point, and every one of the above tells you that someone else is responsible, then write a polite mail to all of them at once, asking for their advice on how to get the Accident Number, since the sum of letter of DATE from Herr T and the phonecall with Frau M in department Q, etc. (list them all, names and dates) has not yet yeilded an Accident Number.
There is a small chance that you might, in fact, not be insured for some or all (at work, on the way to and from work, or also freetime) accidents. This could happen if you do not have an employer at all, or have one for less than 8 hours per week.
In these cases, you should specifically have bought accident insurance from Helsana, your medical insurance ("Krankenkasse") since the basic package is for being sick (krank) and not for accidents. But how any non-insurance-specialist is supposed to know this small detail, when first insuring themselves....!!??
Having said that, some employment perks may include programms by which non-employed spouses are also covered for accidents.
If your accident costs will be not just expensive, annoying or painful, but would really cripple you financially, you may be eligible to get help from the municipality ("Gemeinde") within the Social Security benefits.