Hi Kenna,
Thanks for reaching out to us!
You can use the Pro tab’s Dodge and Burn tools to lighten and darken areas of your photos (respectively). When you have the tool opened, you can paint over the same spot a number of times to intensify it.
If it’s not working well for you or you have further questions, you can send an example photo to our support (over email at support [at] ribbet.com) and we will advise.
– Ben