Parents what would you do?! My sister reopened my stitches!?

I'm going to SEVERELY hurt her! Idc if she is my sister or not! She caused me to get stitches cuz she pushed me in a pool(idc if It was an accident!) I had to get stitches cuz my head hit the ledge! Then now I went to the park with ALL my siblings so it was 11 of us at the park and I was running around playing with the 2 and 4 year old and my sister was swinging and she almost hit my lil sisters so I hurried up and got in the way so they wouldn't get hurt and she jumped of the swing an got mad at me and slapped me and my stitches opened up! My parents are out of town though so they don't know yet.