Best way to thin out the ends of my hair after a bad haircut?

So I got a haircut the other day and the woman was just terrible, its two totally different lengths, WAY shorter than I asked for, (I even provided a photo). Anyway I have delt with it for almost a week now, but my last straw is the fact that it sort of gives me the triangle head since my hair is so thick. It weighs down the top and is poufy at the bottom no matter if I use a flat iron or curl it. So, my question is, what is the best way to have a stylist thin out the ends of my hair? I don't want layers really, since its already so short, but I need the ends to be thinner for sure. She mentioned using "thinning shears", Good or bad? This is the woman who wrecked my hair the first time so I'm trying to be as cautious as can be. =) TIA for your help!