Do i need to change my alternator?

So i have a 2002 honda civic and just wen i thought i was done replacing everything bam i get hit with some more bs. So i just bought a brand new battery in july but today one of my headlights won't fully turn on i thought maybe its just blown but them my kenwood radio that was installed is on demo and can't take it out of it so thats not a good sign so i'm just guessing its the alternator but please anything helps?

Don't guess, get your electrics properly tested. Then you'll know what the problem actually is.

If you get a flat, you change tyres until you find the one that's bad?

Or if your pee smells funny you get kidney transplants, hoping to improve the quality?

Electric problems are amenable to science or engineering for solutions. Have the problem diagnosed by an automotive technician who understands electric circuits. (Hint: Some auto techs have a very bad understanding of electricity. Find a good one.)

Better quit trying to diagnose your car problems. The alternator has nothing to do with the headlights or your radio. The headlight may be a ground problem and the radio may be a blown fuse or just a POS after market radio that happened to fail. You should expect to have to spend more money keeping a 2002 vehicle running. Honda's have a common problem of the valves getting tight and need to be adjusted every 60,000 miles. Then there's the timing belt that needs replacing at 80,000 mile intervals. If none of that has been done you can expect to be doing a valve job when the valves get burnt from being too tight or when the timing belt brakes and bends all the valves.