Expand/Reduce edges of object

Looking at this image you can see that parts of the text are thinner than others:

Is there a way to do this with a tool? Changing the thickness of the text is not what I'm looking for. I want to be able to apply this effect to any element, text of not. Also, even if it's text, maybe I want half of it to be thinner than the other half.

It's almost as if it's "bleeding" in certain areas.

I would like to know if there's a tool that can do this, not only to make them thicker, but also the reverse effect, where it would "degrade" the edges. 

Hope it makes sense.

Thank you! 😊