ORA-00201 and ORA-00202 errors

Today, I recreated SPFILE and by mistake I used the PFILE which belonged to the 11.2.0.4 database instead of 12.1.0 and brought up the database. The value of COMPATIBLE in the 12.1.0.2 parameter file is set to 12.1.0 where as it is set to 11.2.0 in the 11.1.2.0.4 parameter file. After I realized the mistake, I shut down the database, recreated the SPFILE from 12.1.0 parameter file and tried to bring up the database. I am not able to bring up the database anymore and getting the following errors while mounting the database:

Total System Global Area 1.4026E+10 bytes Fixed Size 5299672 bytes
Variable Size 5402264104 bytes
Database Buffers 8589934592 bytes
Redo Buffers 28254208 bytes
ORA-00201: control file version 12.1.0.0.0 incompatible with ORACLE version 11.2.0.0.0
ORA-00202: control file: '/u2004/oradata/m44lb1/cntrl01.dbf'

When I try to recreate the control file, I get the following error:

ORA-01503: CREATE CONTROLFILE failed
ORA-01210: data file header is media corrupt
ORA-01110: data file : '/u2095/oradata/m44lb1/system01.dbf'
ORA-01130: database file version 12.1.0.0.0 incompatible with ORACLE version

It seems that after I initially recreated SPFILE from the 11.2.0.4 Pfile and brought up the database, the version database information in the data file header was updated to 11.2.0.4. Any suggestion to resolve this issue will be appreciated.

Thank you,
Amir