Lump between eyebrows after Botox?

16 days ago i had my botox injection. I had them many times before (forehead). Since two days i can see slightly visible lump between my eyebrows with no color. I feel a lot of heavy pressure between my eyebrows, and a little bit of headache. I know that lumps are common after injections, but i thought they may show up between few hours and couple of days after injection, but not 16 days after like in my example. Im very scared as i heard horrible stories. Please help me. Thank you.