Yes, you should stop the steroids ASAP. Bell's Palsy is extremely common with lyme disease and will go away with treatment. I personally never had Bell's Palsy but know of many who have and it did go away. I'm sure others will post who did have Bell's Palsy.
How long have you had lyme? Were you tested for coinfections?
Anyway, I would start with detoxing (I always recommend that) because as the bacteria die off, they leave toxins in your body which need to come out. When a person is sick their detoxing mechanisms are not working as good compared to a healthy body so one needs help getting rid of those poisons.
I started a thread about detoxing and I will bump it up for you. Start slow and keep it simple to see how you tolerate a detox bath.
I hope that helps,