Unfortunately blepharitis is a chronic condition that often can't be "cured". However, with good eyelid hygiene, antibiotics, and occasionally steroids can help keep the condition asymptomatic. You may need to try a different antibiotic if the tetracycline only helped temporarily. It is also possible that a short course of steroids could minimize the irritation you are currently experiencing. I strongly urge you to get evaluation by an opthomologist, as blepharitis can occasionally be misdiagnosed and the true problem is pathology within the glands themselves. I have pasted some "eye hygiene" information below. I hope this helps.
TREATMENT - The most important initial component of blepharitis treatment is patient education and counseling. Blepharitis is a chronic condition without definitive cure, and a satisfactory result therefore requires a long-term commitment to treatment and appropriate expectations. Goals of treatment are to alleviate acute symptoms of an exacerbation and to develop a maintenance regimen to prevent or minimize future exacerbations.
Good lid hygiene is the mainstay of treatment for all forms of blepharitis and should be emphasized in both the acute and maintenance phases of treatment. Recommendations about self-care hygiene and other interventions are based on clinical experience, as randomized trials have not been reported on specific components of self-care.
Warm compresses - Application of heat to the lids and meibomian glands can liquefy the abnormal solidified meibomian secretions by heating them above their melting point. Heat may also promote increased circulation in the meibomian glands and thereby increase the quantity of secretions.
Patients are advised to soak a wash cloth in warm (not scalding) water and place it over the eyes. As the wash cloth cools, it should be re-warmed and replaced for a total of five to ten minutes of soaking time. This is recommended two to four times a day during the acute phase, and at a decreased frequency in the maintenance phase of treatment.
Lid massage - Lid massage may help empty the meibomian glands and improve secretion, especially in patients with posterior blepharitis and meibomian gland inspissation. Lid massage should be performed immediately following application of a warm compress. Either the wash cloth that was used for the compress or a clean fingertip should be used to gently massage the edge of the eyelid towards the eye with a gentle circular motion.
Lid washing - Patients with significant accumulation of debris on the eyelashes may benefit from gentle washing of the eyelid margins following use of the warm compress. Either warm water or very dilute baby shampoo can be placed on a clean wash cloth, gauze pad or cotton swab. The patient is then advised to gently clean along the lashes and lid margin to remove the accumulated material on the lashes with care to avoid contacting the ocular surface. Vigorous washing should be avoided, as this may incite more irritation of the sensitive eyelid skin.
Commercially available eyelid scrub solutions are safe and effective  and may be preferred for their convenience and ease of use . If any soap is used, thorough rinsing is recommended.
Antibiotics - Since bacterial overgrowth and the lipase activity of colonizing bacteria are known to play a role in the pathophysiology of blepharitis, there is a role for antibiotics in treatment.
Topical antibiotics - Topical antibiotic ointments may be helpful in reducing the bacterial load of the lashes and conjunctiva. The ointment is placed directly onto the lid margin up to four times a day. Many prefer to use the antibiotic once daily at bedtime only, since the ointment can cause significant blurring of vision.
Erythromycin or bacitracin ointments are most frequently prescribed as they have broad spectrum antimicrobial activity and tend to be well tolerated .
Topical azithromycin ophthalmic solution 1% has been shown to improve meibomian gland secretions and to decrease eyelid redness, compared to use of warm compresses alone .