@Henrique Weber, please take the time to have a look at the guidelines before doing any more cuts.

This thread contains guidelines for what we're looking for in our cuts in terms of dimensions, snow, collars, face orientation etc. and video tutorials for each element.

a) Please remember that we want all cuts to include a little bit of collar. At the same time, the ideal cut only contains 2-3 pixels beneath the chin. Since in some sources like this one, the person in the image may have a longer neck than usual, this would be quite difficult to achieve naturally.

Here's a video of the process on how to nudge the collar upwards:

b) This image is not as sharp as the source would warrant. If you want to give this another go yourself, I would recommend using remove.bg, which is a free online tool which removes the background to an excellent standard, for free and almost instantly.

Here's a couple of videos on how to use it, one when combined with Photoshop and another using photopea.com, which is a free online app so close to Photoshop that it has the same shortcuts, layout and icons.

If you don't have Photoshop, photopea.com is the tool I would recommend to use to tweak the draft cut produced by remove.bg. It's more powerful and versatile than GIMP and other similar tools.