Can I return focus to a Textbox when Validation fails as part of a Sub?

As part of a UserForm I am Validating and Formatting in one pass. The problem I'm having is that when the Validation fails, I get the error message, and the focus moves on to the next text box.

I want to trap the user in a loop until they have acceptable data

Private Function CheckNum2(CurValue As String)
    
    On Error Resume Next
    Select Case True
        Case IsNumeric(CurValue)
            CheckNum2 = Format$(CurValue, "#,###.##")
        Case CurValue < 1
            MsgBox ("You must set a value of 1 or greater")
        Case Else
            MsgBox ("You must set a value of 1 or greater")

    End Select

End Function
Private Sub APV_Exit(ByVal Cancel As MSForms.ReturnBoolean)
    
    With APV
        .Text = CheckNum2(.Text)
    End With
    
End Sub