I don’t really think the incision line is a concern, but swelling is. If it is still clearly swollen, and not going down, and especially if it has some redness, call the vet. She may need to be seen or treated if an infection is starting. But if it’s better, not painful, and less swollen, I would just be sure to not let her jump up on anything for a week and keep an eye on it. It will be healing properly if there is less swelling – preferably no swelling at all.
You can’t change the nature of the incision now. It may be something to do with the doctors instruments or style. But if it makes you uncomfortable and your friend has a vet you think you’d like better, you should consider a visit to that vet next. You can either take your bunny to that vet now to give you a second opinion on the healing from the spay, or just finish the process with this vet and go for a wellness exam with the new vet after about a month.