Can a debt collector make a hard inquiry?

Hard inquiries can be quite bad for your credit score. It can drop your credit score by several points. Collection agency inquiries are hard pulls. Repeated queries can drop your credit score.

According to the FCRA Act, if you owe money to a debt collector, they have rights to check your credit report. They can check your credit report to track your recent address and debt. Since the inquiries are directly connected to the financial transactions, they are considered as hard inquiries. You can lose points each time the inquiries occur. However, you can dispute the inquiries, if you believe that you don't owe a debt and the collector us pursuing you in error.

Even if there's a hard inquiry, know that multiple hard inquiries within a 45-day period will be regarded as 1 hard inquiry. However, your credit may drop a bit due to that.
So, if there's a hard inquiry, instead of worrying about it, try to add positive points on your credit report. if you repay the debt, it'll be a positive item on your reports.