Redness in relation to a specific teeth can be due to food impaction in gingival crevice, trauma caused by brushing, infections in the relative area. I hope that there is no growth in your gums and I suspect it to be inflammation. Because with the details provided these alone could be the basic underlying causes. Cleaning once in 6 months is always good and since you had cleaning done before one year better have another professional cleaning.
Next Steps
Best suggestion is to visit your dentist as early as possible. Sort out the problem and eliminate the cause. Because with the details provided its difficult to provide a concrete treatment plan.
Health Tips
Do not prefer self medications, just by starting to brush every time after food consumption is not going to solve it. So get to a professional soon and clear your problem. Get back your happy healthy smiles.