i tried, read below

If you don't mind me saying, I think I know what your problem is. See, what you're doing here is you're just sewing together the biten out part with the other side of the fabric, which doesn't look horrible, but it does give it a look like you just bit a watermelon-shaped ice cream cone or something rather than bit a watermelon. Watermelons are stiffer than that, so what you need to do is have a separate third piece of fabric to put in between both sides of the bite-mark, if that makes sense. If it doesn't... Just cut out a strip big enough to fit, sew the top part of the bite-mark to one side of the strip and then flip it over and do it to the other side - then you'll understand what I mean. You could even go so far as getting a piece of foam to put in the tip and keep it straight if it's not cooperating with you.

Either way, good job with what you have! I really like how simple and cute it is, just like a soft pillow~ The differentiation between the inner and outer bit of the rind only adds to it's cuteness >w< Good luck with your future sewing projects!

actually i did have a piece between the bite mark and i even sewed grooves, however it looked way worse then this and even a friend shook their head at it, so i cut off what i had and ended up sewing the other 2 pieces together. I spend 3 hours on this and a hour alone trying to figure out the bite part, it looked great on the inside but once it was turned inside out it was not what it should have looked like, so i compromised. But thank you for the help, who knows maybe in the future i'll try again.

That's really unfortunate :c I'm sorry it caused you such trouble. I wonder if there'd be any helpful patterns on etsy or pintrist or something? You might get better advice there I'm sure if you decide to pick this project up again. Well wishes your way~

Not everything is going to show teeth marks when you bite into it. I give you A for effort and a sorry for the idea.

Its all good. You helped me learn my limits.