first off, im not gonna say you cant or shouldn't make your own cover. I will also say my own drawing stills are limited to stick figures. But that said, I don't understand why people feel the need to make their own covers, if drawing isn't a very well developed skill? I mean, you can use basically any cover you want. You can find really nice ones online. You almost would never run into situations where the artist will contact you and ask you to take down the cover. So...why not use them? You only have to worry about covers if you are making the story for purchase.
So why bother MAKING a cover, when the internet if full of very well-drawn images that you can use instead? Again, I'm not critiquing your cover. But you can find some very nice images to use instead.
If you're putting the story onto Amazon, for example, i wouldn't say anything. Otherwise, yeah. Find a cover online you like and use that instead.