It's a poor idea to store anything in CSV inside a DB column, because SQL is monumentally poor at string handling - so adding, removing , and altering items from the column string becomes a PITA.
Instead, create an extra table which links you "new values" to to old table. For example, if this was an invoice sytem, youd have an Invoices table and an InvoiceLines table:
CustomerID (Foreign key to Customers table)
InvoiceID (Foreign key to Invoices table)
ProductID (Foreign key to Products table)
You can then add, remove, alter whole row from the InvoiceLines table as needed, and fetch the Line data for a specific Invoice with a trivial JOIN.
It may seem like more work to set up - and it is, a little - but it's a whole load less work than doing anything useful with the CSV data would be later!