I have white spots on my body! please help im scarred!

i have white spots on my shoulders, chest, and back. they use to be not bad, and they would come and go, but just recently they are reallly bad and noticeable and seem to be spreading, and havent gone away. My dad and aunt has also has had it before, but not anymore, they also dont itch or anything.  soo wanting to get them off i went to this website and read this other girls post and the cmnts all said to buy selsun blue dandruff shampoo, soo i did, went home took a shower, and put the selsun all over my shoulders, and chest, and went to bed, i woke up the next day, and it was burning like mad, but i thought i was just burning off the fungus or whatever. soo i watched it off and went to school, well when bedtime came around i took a shower and put the selsun back on determined to fight off these ugly spots, but minutes after puttin on my skin seriously felt like it was on fire, i immedently washed it off, and the next day found 3 scabs on my chest/shoulders. i havent put it back on since, its been three days. and i really want them gone,  am i applying it wrong? am i allergic to it? i just really want to get rid of them. help?