If you used regular cut and paste, the former worksheet is now a Word table.
You can change the font size by applying a paragraph style with the settings
you want to the table or by applying a font size manually (select the whole
table and choose the font size you want).
Another problem may be that the table is falling off the edge of the "paper."
Try modifying the table width (in table properties) to something less than
the text area width (say, 6 inches). If that works, then you can reset the
width to what you want. If that does not work you will need to temporarily
change the orientation and perhaps the paper size so you'll be able to see
all the borders and drag them.
I have to do this often. If someone has a better method, I'd like to hear
about it.
Tip: Setting the font, and font size, and column/table widths that will fit
the Word text area width before you copy an Excel file into Word can greatly
reduce the cleanup in Word.
Pam