Yes, if you get injured or sick, or in case of emergency, you can visit or be taken to the 24-hour medical service (SMURD) whose location will be indicated onto the festival map.
Most accidents can be avoied by respecting a few simple rules: No drugs. Take breaks from the music regularly. Hydrate and eat. Use sunscreen if needed. Do not throw bottles or glasses in the camping area. Use shoes. Use a flashlight at night. Don’t fight!
Note: if you are under any treatment, you should pay attention to bring your own medecine with you. First aid isn’t a pharmacy.