Swelling in the gums is an indication for gingivitis and since you are also having discoloration so this means that the gums are not receiving adequate blood supply.
It is suggestive to visit a dentist and get your gums clinically evaluated. Also start brush twice daily. Before brushing floss each and every tooth properly, then brush your teeth with proper technique as shown in the link....http://www.identalhub.com/article_why-do-we-need-to-brush-our-teeth-156.aspx
After brushing do mouthwash gargles and don't eat or drink anything at least for an hour post rinsing and keep a check on detrimental oral habits like smoking, eating sticky food etc. For more info on ginvitis visit the link....http://www.identalhub.com/articlecategory-gum-diseases-9.aspx
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