This is Jennifer, oh you poor darling.
Firstly I think you have an acid burn. I just posted a LONG story on acid burns and damaged skin. Can I suggest you read it as I think it may help you and provide some soothing. Read it first then this
Also it looks like you still have your peg in. When they do the surgery they pull the bowel through the hole they have made to stop the bowel sliding back into the abdomen they slide a peg under the loop and stitch it in place. I had my peg removed after two days. They need to wait until the skin retracts around the stoma then the loop stays in place outside the body. Yours may still be there because your skin hasn't retracted, but it is very important that you speak to your doctor about it.
After you have got to the end of my acid burn post if possible lay down with a mirror so you can see the stoma. I put the new bag and two rings down my bra to warm them while I'm doing all of preparation. Take one of the rings and break about a quarter off, rub it between your fingers to really soften it. Remember that in my acid burn post you have already barrier wiped the whole area. Use the softened barrier ring to fill in the dent from your stoma towards the belly button only go as far as the large inner ring which is about the distance to the barrier ring. Smooth it out so that it fades to nothing (I hope this makes sense). The second barrier ring is gently stretched out so that the centre hole is the same size as your stoma, gently press into pace. Take the bag and position it over the stoma and press down make sure that the flange is smooth. I get a cloth and open the viewing area to rub the cloth around the whole area around the stoma. Hold your warm hands over the bag to help it adhere hold for at least one minute.
Because it looks like you still have a peg in the stoma you have to make sure that it is in the bag not under the barrier ring or flange. To make sure that the peg and any bowel is in the bag gently manoeuvre the opening of the bag around the peg before pressing the bag into place don't get any faeces on the sticky side of the bag, it won't stick.
You will get used to all this eventually and as your wounds heal and your health improves things get easier.
PLEASE DON'T GET STRESSED WHEN THINGS DON'T ALWAYS WORK JUST CLEAN UP START AGAIN AND DON'T BECOME AFRAID OF IT
Hugs Jennifer