One thing to work on if you don't want to have panel borders is the placement of the speech bubbles. When you have no panel borders it becomes really important that each panel guides your eye towards the correct place to start reading the next panel. Since you're using such basic art and there are so many speech bubbles in this page you just posted, they should be the primary means of doing that.
The place in the comic page where this becomes a problem is between the first and the second panel. You have two speech bubbles directly on top of each other ("Why?" and "Is it my art?") with little space between. That means that the eye is going to be guided from the top one to the bottom one. This is a problem because you're reading the speech bubbles in that panel out of order (you should be reading "Why do I keep hurting myself?" first).
In the West we're conditioned to read comics left to right both in pages, and in each panel. But you have to make sure you help people along in that respect.
There's way more to learn about guiding people's eyes through comic pages, though. I'd recommend checking out the book Making Comics by Scott McCloud.