I had my laser tattoo removal treatment done and have a blister in one area. Is this normal?

Sometimes. It is possible there was alot of ink in that area and that is why you got a blister -apply vaseline or aquaphor twice a day till it heals and hopefully you will not get a scar.
Probably. Blister formation is a common complication in laser tattoo removal especially in large black tattoos and red inks. It does not mean it was incorrectly lasered but needs care. Keep it clean and apply a topical antibiotic like Neosporin provided you are not allergic.
Yes. His is a common occurrence post treatment. Discuss with your treatment center to explore recommendations around how best to manage this.