I can't see any scratches, but assuming the bumper is plastic, you can take the bumper off, and use a heat gun (GENTLY) dont heat up the dent to much, and push the dent out from the back side. When you have the dent pushed out, put water on the dent. You may have to repeat this a few times until satisfied. If it doesnt work, sadly it's a job for a body shop. Shouldn't cost to much.
If you want to post pictures from a hosting site, try this-
Open a free account on a site such as Photobucket. Upload your picture to your account. Open the picture and copy the URL that has IMG tags. Paste it into the response box here and the pictures should appear in your post.
found a minor scratch on the car body, its a thin line. Any recommendation? would using mazda's touch up pen fix it? Thank you
Also, I have rust protection with mazda, any need for rust treatment or minor scratch won't affect.
In my experience with the OEM Mazda touch-up pen, I found that it helps more on filling mild to deep paint scratches, small areas of paint scraping and very small paint dents as well.
Using the touch-up pen on fine scratches makes the paint to "seat" over the scratch , not filling the scratch or letting the paint from the pen to integrate with the already existing car paint coating.
Also if you purchase the touch-up pen I would recommend you to shake the pen between 5-10min for best results (Im not kidding, the shaking makes a lot of difference when applying the paint over the car body, as the color from the pen will match more the paint on your car but not 100%)
Additionally, I have used Meguiar's Ultimate Compound on fine scratches and pretty much it helps a lot to remove fine scratches from my car's body.(Deeper Scratches cannot be removed with Ultimate Compound in my experience with the product)
Finally, the touch-up pen does not work miracles, it helps you cover those scratches and to make them less visible, it does what is suppose to do, but if you need to really fix scratches or dents 100% then take your car to your official Mazda dealership or to a professional body shop.
I hope this was helpful!