First, let's calculate the interest that Doug will be charged on his unpaid balance. The interest rate is 2.5% per month, so he will be charged 2.5% * $923.7 = $23.09 in interest.
Then, we need to add the late fee of $25.00 to the interest charge. This means that Doug will owe a total of $23.09 + $25.00 = $48.09 in addition to his unpaid balance.
So, Doug will owe a total of $923.7 + $48.09 = $971.79 on his credit card after one month.