I am not sure if my side effect is from using Singulair or not. ...

I am not sure if my side effect is from using Singulair or not. I just started taking the Singulair 10mg last Thursday only in the evenings. After 3 days my face was swollen to the point that I couldn't see. I went back to the doctor and he didn't think the Singulair had anything to do with it since he was treating me for a contact dermatitis chemical burn so I still continue to take the Singulair but the swelling hasn't gone away yet and it has been 3 more days. If anyone can shed some light on if this is a side effect from using Singulair it would be appreciated. I also am taking Xyzal in the mornings so therefore I am not sure if this is what caused my face to swell. Any replies would be appreciated.