I'm pretty sure there is no better editing app than Photoshop, especially for PC. At first, it looks very difficult, but if you watch several video-lessons, you understand how it works.
For mobile phones, the choice is huge. VSCO, Snapseed, PicArt and so on. They're all great at photocorrection. If I need more than that, I use retouchme . I prefer it for being multifunctional.
To go through chemo therapy or choose not to?