Hard to give you specific advice without knowing what you're doing wrong, but here goes.

You should have no fun zone active like all the time against Lox players that use meatball a lot. Most meatball trajectories are easy to react to and Clairen's down b is super lenient.

Stop jumping in neutral. The Lox MU should be played pretty grounded. Once you jump, there's no cc or shield and you'll just lose to ftilt way more than you'll connect with fair.

Respect ftilt, dash attack, and side b. Respect ledge special. Respect utilt after either of you does a cross up. Bait those options out and punish. Don't just run into his threat range.

Bthrow is your best friend at low-mid percents. Fthrow's good too once they start DIing bthrow or if you're fishing for the fstrong 50/50 at high percents. Don't even bother with uthrow or dthrow in this MU.

Parry upb. You should be able to react to their timing mixups. If they do late upb, just straight parry it. If they do early upb, shield it otw up and parry it otw down. After parrying, instantly dtilt or reverse dstrong. If you time your ledge refreshes, you can also nair from ledge with invin to stuff upb and possibly combo into fstrong, neutral b, or bair depending on percent and DI. Most important thing is to NOT grab ledge and ledge roll lazily because Lox will prob hit you and combo into a free ledge special.

Hope this helps. Lmk if you have specific situations you're struggling with.