I brewed a 6 gallon Mexican ale, it was just after the high krusen phase. The Carboy was in the garage. Temperature outside was between 70&80 degrees. Brought it inside. Put some yeast believe just the regular beer yeast in the Carboy with a cup of sugar. In the room I placed it was the normal brew temperatures. Was any damage done to the Beer?
Only "damage" would be from the high temp you had during fermentation. Fusel alcohols, undesirable esters.
Adding more yeast and sugar will only get it fermenting again and raise the ABV up a bit.