Setting focus on a textbox in userform on Excel VBA

I have two userforms: frmTradeSickOther and frmOther. When I click "Other" option in frmTradeSickOther, it'll call frmOther. I am trying to get the user to enter some text in a textbox in frmOther and then click on the button "Add Comment". If the user clicks on "Add Comment" button without typing anything in the textbox, a message box will come up telling the user to type something in.

My Problem: I am trying to get the cursor to automatically go to the top-left corner of the textbox and blink once the user is returned to frmOther after the error message.

I got the cursor to go to the text box when frmOther is called from frmTradeSickOther by adding the following code (See line 67-71 in the attached file):

Private Sub optOther_Click()
    Unload Me
    frmOther.Show
    frmOther.txtOther.SetFocus
End Sub