This sounds like a really difficult situation, and I think it's really brave you reached out by posting here. It's a bit hard to know what to suggest other than saying that your safety and your family's safest is of utmost importance in situations like this.
Also, if you have physical wounds, those would be considered evidence just as much as what you and other members of your family said. However, reporting things like this would likely require a lot of intervention from police, medical professionals, social workers, etc.. It might also mean leaving your home and/or being separated from the rest of your family, depending on what happens. I don't think it would be right of us to offer advice without you understanding what your options are, and what the impact of those options might be.
This isn't to say that I don't think you should report what is going on, but only that I think you need some more information. Which we can't provide.
I also don't honestly know how much can be done if abuse is reported secondhand. Potentially not a lot. I also don't know that if it's reported secondhand you would be removed from your home or your father would be immediately. That's why again, I think you might need to reach out to some anonymous resources first to find that out, since all of your concerns are absolutely valid.
Have you tried something like RAINN's online chat? I don't know your age in terms of consent and what can be kept private from family, but RAINN could advise you best on what would be specific to your location if you are in the USA. It's online, so you don't have to worry about a phone call or anything like that.
If a phone call felt like an option you could also try this national hotline and website I found, again US based:
I know for example my local county has an abuse hotline/phone number just for them. Your county might also has similar. Same with a child advocate organization. We have one specific to my county, so those are things that if you have internet access, you might try looking up as well to get some more local resources. We also have local teen/child homeless shelters for folks to stay, but unfortunately if you are under certain ages and you go to those, they often require parental consent to stay overnight. So again, finding out what local resources you have would be really good. I'm NOT saying post your specific location here, only that you might need to do some research on this to find out.
If you aren't in the USA, knowing your location (at least country) and age would help us try to come up with resources to suggest to you that would be more relevant.