I Have A Small Indent/hole On The Bottom Right Side

I have a small indent/hole on the bottom right side of my mouth just below my molars and it hurts like a canker sore. I'm really worried that I have periodontal disease. I've been really stressed out lately so hopefully it's just come up from stress. I've also not been too great on my brushing lately because I've just forgotten to. I couldn't develop periodontal disease just from a week of poor brushing, right?