Been working almost four years now.
I just need to vent.
I'm 31, I run machines at a factory around Hua Hin/Cha-am. Job's tough, smells like oil sometimes, dusty, but once you get used to it it's bearable. The problem is the people at work and the bosses' attitudes.

I'm so confused. Tired. Pretty discouraged.
Short version: I've always given my all. I teach new people, do overtime. I come in around 5:30am to check the machines before everyone else. The first two hours I'm basically running around fixing stuff. When problems pop up I'm the one running to sort them out. We've got this new project to change the production line — me and the guy on the same machine designed how to set it up and actually cut the rejects. We tested it for like three back-to-back shifts. Each setup run took about 1 hour 20 minutes. I scribbled little notes on old scraps of paper and stuck them on the machine — ripped paper, faded pen — but when the results came out the boss announced it in the meeting and gave full credit to the person who suggested the idea earlier (some engineer who just popped in that day). I barely heard my name at all, even though I was the one who tested and fixed everything. People see me grinding every day, so why does it feel like I'm being ignored like this? Or am I overthinking it?

Silence after that.
Sometimes I tell myself it's because I dress plain, wear flip-flops on days off, or I'm not good-looking enough. Sounds stupid when I say it, but those thoughts creep in. Does that make people see me as equal to others? No idea.

Another thing: last month a boss called me into the machine room and told me to improve performance but didn't give any clear guidance. When the results were good, there were compliments among management, but only generic praise — no details about who did what. I feel like no one stood up for me when mistakes were highlighted, but when things go right others chat about it at the lunch table. I just overhear it like it's news, not a proud moment I get to hear myself. Weird.

I'm not the kind to blow up or make a scene. I've been bottling it up but it's starting to get to me. The feelings pile up like people don't really see the effort. I'm really down about it, like really T_T

Sometimes I think about talking to the boss straight up, but I'm worried I'll just sound like a complainer or like I'm jealous. On the other hand, if I stay silent this keeps happening. Should I start documenting my work properly — save proof in files and email a summary to the boss? But in our factory, being too formal might come off cold. Ugh I dunno 5555

I really want some confidence or real advice on what to do. Talk politely and directly, or send a monthly report? What do you guys think — what should I do?

P.S. Sorry if this is messy. Typing on my break on an old phone that runs out of battery a lot.