You cannot get an FHA loan if your credit score is below 620,
since it is backed by the government, they have very strict
guidlines on the process. However, if you work with a mortgage
lender that does FHA, often times they have "credit rescoring"
prgrams that will tell you exactly what you need to do to get your
score to the 620 that you need. Once you do what they need, they
can do a rescore and it will raise you credit. Good luck!