You should write to the journal immediately explaining that this was a mistake. You should also write to your colleague who is the corresponding author of the manuscript explaining the mistake you have made and asking him/her to also get in touch with the journal to corroborate that you have made an honest error.

Please follow  up with the journal until you receive a confirmation that the error has been corrected and your contribution acknowledged.

Related reading:

• Corresponding author assigns co-authors without their knowledge: A case study
• The final manuscript should be approved by the co-authors before submission
• Who can be included as a co-author of a paper?