Drop down list to ifs

[meenank]

Can some one tell me why I'm not able to see this column ( follow up) in my app. Or can any one suggest a better option

Thank you for your support

The app formula is

 IFS([Follow up]= "<1 week", DATE([Date of examination])+ 3,
[Follow up]= "1 week", DATE([Date of examination])+ 7,
[Follow up]= "2 weeks", DATE([Date of examination])+ 14,
[Follow up]= "3 weeks", DATE([Date of examination])+ 21,
[Follow up]= "4 weeks", DATE([Date of examination])+ 28)