Need to append text to a specific html tag in a Confluence page

[Daniel Baron]

I want to add a line of text after an html tag with the id skillLevel. I can find the id and get the text back but how to I actually update it? 

    var skillString = "<p> " + users_name + " - " + email + '</p>';
    var skillName = input.name;
    var skillLevel = input.value;	
    $.get('/rest/api/content?spaceKey=EXPERTISE&title=' + skillName + '&expand=space,body.storage,version,container', function (data, status) {
        var pageData = data.results[0];
	var existing_body = pageData.body.storage.value;  
        pageData.version.number += 1;
        var page_id = pageData.id;	  
	var target_bin = $(existing_body).find('#' + skillLevel);

        // This will print out the text I want to add a line to.
        alert(target_bind.text());

        // Neither of these two ways to update seem to work.
	//$('#'+skillLevel).append(skillString);
        //$(target_bin.text()).append(skillString);
        }
	$.ajax({
          type: "PUT",
          url: "/rest/api/content/" + page_id,
          data: JSON.stringify(pageData),
          contentType: "application/json; charset=utf-8",
          success: function (data) {
            alert("Successfully added info");
          }
        });
   });