Using glyphicon icons instead of other icons (fa icons), I am able to change the color of the icon, but it does not completely fill the icon with color like Facebook's like button.
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel = "stylesheet" href = "http://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css">
<div id="${botId}-like-dislike-ctl">
<button class="btn" style="color:blue;" id="red"><i class="glyphicon glyphicon-thumbs-down" aria-hidden="true"></i></button>
<button class="btn" style="" id="green"><i class="glyphicon glyphicon-thumbs-up" aria-hidden="true"></i></button>
</div>