In this great tutorial I will show you a trick on how to make an animation where Britney Spears gets a makeover, and the makeup colors change graduatley.

1.
Start by going to File -> Import -> Import to stage, and locate the image you want to add this effect to.

2.
With the zoom tool drag a square around the mouth so you zoom in to the mouth.
Now with the line tool click and draw around the outside of Britneys lips.

3.
Now with the mouse, get close to the lines you just drew, and drag them so they get rounded as shown in the image below.

4.
Do the same for the inside of the lips, so you have drawn as shown below.

5.
Zoom out, select all the lines you have made, right click and choose break apart.
With the paint bucket tool click inside the lips to make a fill, and then click once on the lines around the lips and hit delete so you have the filling in the lips.

6.
Right click the lips shape and choose convert to symbol and choose movie clip.
Now go to the shapes properties panel and set the alpha to about 50, brightness to 0, and the tint to 50

7.
Double click the lips to get into the lips movie clip.
Now as you see from the image above, I have choosen the color red as the start lipstick.
In the timeline right click at frame 10 (depends on how fast the change should be) and choose Insert keyframe.

8.
At frame 10 change the lips color to another bright color, I choose green.
Now between the two key frames in the time line right click and choose Create motion tween.
Now for both the first keyframe and keyframe 10, right click the lips shape and choose break apart, to make convert the shapes to raw shapes.

9.
Make some more keyframes at frame 20, 30 and 40 and repeate step 7-8 to make more color changes.

10.
Go out to the root of the stage and try to play the sequence you should now see the mouth color changing.

And you are done, I my final image, I did the same to both eyes, just for fun.