Hey, I can promise you that every human being has this problem. Nobody looks at their reflection in the mirror and comes away without the desire to change something about themselves. I know I don't.
Like you, there are days I feel like I have decent, passable features, but there are also days where I feel like not a single damn thing looks okay.
I don't remember where I first heard this advice, but it's worked for me so far. Every day you look into your mirror, step out of the mindset that you're looking at yourself. You're facing a stranger, a different person - no, a FRIEND. Look carefully at this friend's face. You really like this friend. She's been with you every day of your life. She's stood right across from you when you cried. Take a good, long look at her. Notice how familiar this face is to you. She's the face you see the most. Aren't there a lot of things you actually like about this face? Things you've gotten attached to. Things that have grown on you over the years. Things that have changed since the time you saw this face eight years ago, five years ago, ten months ago. Smile at her. REALLY smile at her. And while you're smiling, say thanks to her. Watch how she's smiling back at you. Isn't she so cute? You adore her.
The one rule to remember always: don't tell your reflection anything you wouldn't tell your friends. It's a seriously strange phenomenon that we can always see the good and beauty in our awesome friends, but we can't do the same for ourselves.
I used to have really bad body dysmorphia and hated my facial features. It really helped when someone told me to stop standing in front of my mirror and inspecting myself, holding myself to ridiculous self-imposed standards. Now, after I shower, I sit down on the floor close to my mirror and look at myself like I'm looking at a friend - I don't hold my friends to any kind of standard, I just instinctively like them for who they are and their appearance is just part of the package.
TL;DR : if you can't change yourself, change the way you look at yourself