PL/SQL :: Exception Handling In Procedures

I am using for writing text files data to database. The problem here is let us assume there are 6 records in text file and if there is a problem at 2nd record, the later records are not getting inserted.

CREATE OR REPLACE PROCEDURE PROC1
IS
temp varchar2(500);
tmp_name varchar2(5);
tmp_no varchar2(4);
.
BEGIN
WHILE NOT end_of_file
LOOP

IF i = 18 THEN
tmp_no := temp;
END IF;

IF i = 21 THEN
tmp_name := temp;
END IF;

END LOOP;
END;
/If i=18 and temp = '12345' here, then tmp_no := temp; won't work (tmp_no varchar2(4);)
Similarly, If i=21 and temp = 'ABCDEFG' here, then tmp_name := temp; won't work (tmp_name varchar2(5));

how to handle this through EXCEPTIONS so that even if there is a problem with 1 record, while loop remain working for further records..