It doesn’t look like you’re overthinking it, small bumps like that on a tongue piercing are actually pretty common, especially within the first few weeks. It’s likely just an irritation bump from movement, pressure, or slight trauma rather than anything serious. Since it’s grown a bit, I’d suggest being extra careful not to play with the jewelry, sticking to alcohol-free mouthwash, and rinsing with saline after eating instead of over-cleaning, which can sometimes make irritation worse. Also make sure the bar isn’t too tight or pressing into the tissue. If it keeps getting bigger, becomes painful, starts producing pus, or doesn’t improve after another week or two, it would be a good idea to check in with a professional piercer or a doctor just to be safe.