Weird bugs in my rats fur?

so about 4 days ago i saw a little black speck at the base of one of my rats whiskers. i thought that it was just a small scab so i left it alone and it stayed the same size for about 3 days. and yesterday when i took her out it was 6 times its size. it was maybe a centimeter long and it was rectangular. it looked like it had a tiny wing but i could be mistaken and it was black. i took it off an she bled some but i got a Q-tip and and put some water on it to wash off the blood and she is acting fine now. does anybody know what it might be?