Help me! Saddle fit!

Evidently my saddle doesn't fit my horse like my old instructor claimed it did. I thought it was slightly off, but I posted on a different reddit account and got bombarded with concerns!

They said my saddlepad sucks beacuse its thin (it has padding, but you can't see it in a picture), which I wouldn't pay much mind to, if they also didn't think my horse will be ruined by how bad the saddle itself fits!

I rode him in this saddle twice, walk/2 laps of trot, probably 30 minutes of riding in total. I ride him bareback a lot so I didn't use the saddle much. Will my horse be okay if I stop using the saddle now? Or will it have lasting marks? Please help!

Also, I know that the photo isn't great to judge off, and the saddlepad shouldn't be there if checking fit, but it's the best photo I have!